SKILL Language Reference
Product Version 06.40
August 2005
Updated September 2005
1990-2005 Cadence Design Systems, Inc. All rights reserved.
Printed in the United States of America.
Cadence Design Systems, Inc., 555 River Oaks Parkway, San Jose, CA 95134, USA
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information of Cadence or its licensors, and is supplied subject to, and may be used only by Cadence’s
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Restricted Rights: Use, duplication, or disclosure by the Government is subject to restrictions as set forth
in FAR52.227-14 and DFAR252.227-7013 et seq. or its successor.
SKILL Language Reference
August 2005 3 Product Version 06.40
Preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
About the SKILL Language . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
SKILL Development Helpful Hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
SKILL API Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Document Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
SKILL Language Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
abs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
acos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
add1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
addDefstructClass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
alias . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
alphalessp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
alphaNumCmp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
and . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
append . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
append1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
apply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
argc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
argv . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
arrayp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
arrayref . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
asin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
assoc, assq, assv . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
atan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
atof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
atoi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
atom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
bcdp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
begin - SKILL mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Contents
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begin - SKILL++ mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
bitfield1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
bitfield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
blankstrp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
bnand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
bnor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
bnot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
booleanp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
bor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
boundp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
buildString . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
bxnor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
bxor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
caar, caaar, caadr, cadr, caddr, cdar, cddr, ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
car . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
case, caseq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
cdr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
cdsGetInstPath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
ceiling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
changeWorkingDir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
charToInt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
clearExitProcs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80
close . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
compareTime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
compress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83
concat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
cond . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
cons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
constar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
copy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
copy_<name> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
copyDefstructDeep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
cos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
cputime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
createDir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
csh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
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declare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
declareLambda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
declareNLambda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
declareSQNLambda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
define - SKILL++ mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
defmacro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
defMathConstants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
defprop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
defstruct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
defstructp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
defun . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
defUserInitProc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
defvar - SKILL mode only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
deleteDir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
deleteFile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
difference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
do - SKILL++ mode only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
drain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
dtpr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
ed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
edi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
edit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
edl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
envobj . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
eq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
equal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
eqv . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
err . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
errset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
errsetstring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
eval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
evalstring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
evenp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
exists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
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exit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
exp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
expandMacro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
expt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
fboundp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
fileLength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
fileSeek . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
fileTell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
fileTimeModified . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
fix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
fixp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
float . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
floatp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
floor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
for . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
forall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
foreach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
fprintf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
fscanf, scanf, sscanf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
funcall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
funobj . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
gc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
gensym . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
geqp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
get . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
get_filename . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
get_pname . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
get_string . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
getc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
getchar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
getCurrentTime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
getd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
getDirFiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
getFnWriteProtect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
getFunType . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
getInstallPath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
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getLogin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
getPrompts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
getq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
getqq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
getTempDir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
gets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
getShellEnvVar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
getSkillPath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
getSkillVersion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
getVarWriteProtect - SKILL mode only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
getVersion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
getWarn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
getWorkingDir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
go . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
greaterp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
if . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
importSkillVar - SKILL++ mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
infile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
inportp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
inScheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
inSkill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
instring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
integerp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
intToChar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
isCallable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
isDir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
isExecutable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
isFile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240
isFileEncrypted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241
isFileName . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
isInfinity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
isLargeFile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
isLink . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
isMacro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
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isNaN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
isReadable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
isWritable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250
lambda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
last . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252
lconc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
leftshift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
leqp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
lessp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257
let - SKILL mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258
let - SKILL++ mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
letrec - SKILL++ mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
letseq - SKILL++ mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
lineread . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
linereadstring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270
listp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
listToVector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
loadi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275
loadstring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
log . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279
log10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280
lowerCase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281
make_<name> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
makeTable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283
makeTempFileName . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
makeVector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286
map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
mapc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
mapcan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
mapcar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
maplist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
max . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
measureTime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
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member, memq, memv . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300
min . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302
minus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
minusp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304
mod . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
modf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306
modulo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307
mprocedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309
nconc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311
ncons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313
needNCells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314
negativep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315
neq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316
nequal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317
newline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
nindex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319
nlambda - SKILL mode only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
not . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
nprocedure - SKILL mode only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
nth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
nthcdr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326
nthelem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327
null . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328
numberp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 329
numOpenFiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330
oddp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331
onep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332
openportp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333
or . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334
otherp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335
outfile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336
outportp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338
pairp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339
parseString . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340
plist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342
plus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343
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plusp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 344
portp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345
postdecrement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346
postincrement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347
pprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348
predecrement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349
preincrement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350
prependInstallPath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351
print . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352
printf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
printlev . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355
println . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 357
procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358
procedurep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362
prog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363
prog1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
prog2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366
progn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367
putd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 368
putprop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370
putpropq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371
putpropqq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373
quote . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374
quotient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375
random . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376
range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377
read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
readstring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 380
readTable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382
realp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383
regExitAfter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 384
regExitBefore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 385
remainder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386
remd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387
remdq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389
remExitProc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391
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remove . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392
remprop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394
remq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
renameFile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396
return . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397
reverse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399
rexCompile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400
rexExecute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403
rexMagic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404
rexMatchAssocList . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 406
rexMatchList . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408
rexMatchp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409
rexReplace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410
rexSubstitute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412
rightshift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
rindex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
round . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415
rplaca . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416
rplacd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
schemeTopLevelEnv . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418
set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419
setarray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420
setcar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
setcdr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423
setFnWriteProtect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424
setof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425
setplist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427
setPrompts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 428
setq . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430
setqbitfield1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432
setqbitfield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433
setShellEnvVar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434
setSkillPath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435
setVarWriteProtect - SKILL mode only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437
sh, shell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
simplifyFilename . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440
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sin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441
sort . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442
sortcar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 444
sprintf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446
sqrt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 448
srandom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449
sstatus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450
status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453
strcat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 454
strcmp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 455
stringp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 456
stringToFunction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 457
stringToSymbol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458
stringToTime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459
strlen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 460
strncat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 461
strncmp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 462
sub1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 464
subst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465
substring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 466
sxtd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468
symbolp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469
symbolToString . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 470
symeval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 471
symstrp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 472
system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 473
tablep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474
tableToList . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475
tailp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 476
tan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477
tconc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 478
theEnvironment - SKILL++ mode only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480
times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483
timeToString . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 484
timeToTm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 485
tmToTime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 487
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truncate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489
type, typep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 490
unalias . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 491
unless . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 492
upperCase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493
vector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 494
vectorp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495
vectorToList . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 496
vi, vii, vil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 497
warn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 498
when . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500
which . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
while . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 504
writeTable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 505
xcons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506
xCoord . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507
xdifference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 508
xplus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 509
xquotient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 510
xtimes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511
yCoord . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 512
zerop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 513
zxtd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 514
A
Scheme/SKILL++ Equivalents Tables. . . . . . . . . . . . . . . . . . . . . . . . . 515
Lexical Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 516
Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 517
Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518
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Preface
This manual is for the following users
■ Programmers beginning to program in SKILL
■ CAD developers who have experience programming in SKILL, both Cadence internal
users and Cadence customers.
■ CAD integrators.
The companion for this manual is the
SKILL Language User Guide, which
■ Introduces the SKILL language to new users
■ Leads users to understand advanced topics
■ Encourages sound SKILL programming methods
See also:
■ About the SKILL Language on page 16
■ SKILL Development Helpful Hints on page 17
■ SKILL API Documentation on page 18
■ Document Conventions on page 19
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About the SKILL Language
The SKILL programming language lets you customize and extend your design environment.
SKILL provides a safe, high-level programming environment that automatically handles many
traditional system programming operations, such as memory management. SKILL programs
can be immediately executed in the Cadence environment.
SKILL is ideal for rapid prototyping. You can incrementally validate the steps of your algorithm
before incorporating them in a larger program.
Storage management errors are persistently the most common reason cited for schedule
delays in traditional software development. SKILL’s automatic storage management relieves
your program of the burden of explicit storage management. You gain control of your software
development schedule.
SKILL also controls notoriously error-prone system programming tasks like list management
and complex exception handling, allowing you to focus on the relevant details of your
algorithm or user interface design. Your programs will be more maintainable because they will
be more concise.
The Cadence environment allows SKILL program development such as user interface
customization. The SKILL Development Environment contains powerful tracing, debugging,
and profiling tools for more ambitious projects.
SKILL leverages your investment in Cadence technology because you can combine existing
functionality and add new capabilities.
SKILL allows you to access and control all the components of your tool environment: the User
Interface Management System, the Design Database, and the commands of any integrated
design tool. You can even loosely couple proprietary design tools as separate processes with
SKILL’s interprocess communication facilities.
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SKILL Development Helpful Hints
Here are some helpful hints:
■ You can click Help in the SKILL Development Toolbox to access SKILL Development
Help for information about utilities available in the toolbox. The Walkthrough can guide
you through the tasks you perform when you develop SKILL programs using the SKILL
Development Toolbox. You can also find information about
SKILL lint messages, and
message groups.
■ You can use the SKILL Finder to access syntax and abstracts for SKILL language
functions and application procedural interfaces (APIs).
■ You can copy examples from windows and paste the code directly into the Command
Interprete Window (CIW) or use the code in nongraphics SKILL mode. To select text
❑ Use Control+drag to select a text segment of any size.
❑ Use Control+double-click to select a word.
❑ Use Control+triple-click to select an entire section.
For more information about Cadence SKILL language and other related products, see
■ SKILL Development Help
■ SKILL Development Functions Reference
■ SKILL Language Functions Reference
■ Interprocess Communication SKILL Functions Reference
■ SKILL++ Object System Functions Reference
Note: The
Cadence Installation Guide tells you how to install the product.
For more information about Cadence SKILL language and other related products, see
■ SKILL Development Help
■ SKILL Development Functions Reference
■ SKILL Language Functions Reference
■ Interprocess Communication SKILL Functions Reference
■ SKILL++ Object System Functions Reference
Note: The
Cadence Installation Guide tells you how to install the product.
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SKILL API Documentation
Cadence tools have their own application procedural interface functions. You can access the
SKILL function references in the CDSDoc library by selecting Docs by Product and opening
the SKILL folder. The set of books you will find there include the following:
■ Cadence Design Framework II SKILL Functions Reference contains APIs for the
graphics editor, database access, design management, technology file administration,
online environment, design flow, user entry, display lists, component description format,
and graph browser.
■ Cadence User Interface SKILL Functions Reference contains APIs for
management of windows and forms.
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Document Conventions
The conventions used in this document are explained in the following sections. This includes
the subsections used in the definition of each function and the font and style of the syntax
conventions.
Section Names and Meaning
Each function can have up to seven sections. Not every section is required for every function
description.
■ Syntax
The syntax requirements for this function.
■ Prerequisites
Steps required before calling this function.
■ Description
A brief phrase identifying the purpose of the function.
A text description of the operation performed by the function.
■ Arguments
An explanation of the arguments input to the function.
■ Return Value
An explanation of the value returned by the function.
■ Example
Actual SKILL code using this function.
■ References
Other functions that are relevant to the operation of this function: ones with partial or
similar functionality or which could be called by or could call this function. Sections in this
manual which explain how to use this function.
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Syntax Conventions
This list describes the syntax conventions used in this document.
literal (LITERAL) Nonitalic (UPPERCASE) words indicate keywords that you must
enter literally. These keywords represent command (function,
routine) or option names.
argument (z_argument)
Words in italics indicate user-defined arguments for which you
must substitute a name or a value. (The characters before the
underscore (_) in the word indicate the data types that this
argument can take. Names are case sensitive. Do not type the
underscore (z_) before your arguments.)
| Vertical bars (OR-bars) separate possible choices for a single
argument. They take precedence over any other character.
[ ] Brackets denote optional arguments. When used with OR-bars,
they enclose a list of choices. You can choose one argument
from the list.
{ } Braces are used with OR-bars and enclose a list of choices. You
must choose one argument from the list.
... Three dots (...) indicate that you can repeat the previous
argument. If you use them with brackets, you can specify zero or
more arguments. If they are used without brackets, you must
specify at least one argument, but you can specify more.
argument... ;specify at least one,
;but more are possible
[argument]... ;you can specify zero or more
,... A comma and three dots together indicate that if you specify
more than one argument, you must separate those arguments by
commas.
=> A right arrow points to the return values of the function. Variable
values returned by the software are shown in italics. Returned
literals, such as t and nil, are in plain text. The right arrow is
also used in code examples in SKILL manuals.
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/ A slash separates the possible values that can be returned by a
SKILL function.
Note: The language requires any characters not included in the list above. You must enter
required characters literally.
SKILL Data Types
Prefix Internal Name Data Type
a array array
b ddUserType Boolean
C opfcontext OPF context
d dbobject Cadence database object (CDBA)
e envobj environment
f flonum floating-point number
F opffile OPF file ID
g general any data type
G gdmSpecIlUserType gdm spec
h hdbobject hierarchical database configuration object
l list linked list
m nmpIlUserType nmpIl user type
M cdsEvalObject —
n number integer or floating-point number
o userType user-defined type (other)
p port I/O port
q gdmspecListIlUserType gdm spec list
r defstruct defstruct
R rodObj relative object design (ROD) object
s symbol symbol
S stringSymbol symbol or character string
t string character string (text)
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u function function object, either the name of a function (symbol) or
a lambda function body (list)
U funobj function object
v hdbpath —
w wtype window type
x integer integer number
y binary binary function
& pointer pointer type
Prefix Internal Name Data Type
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SKILL Syntax Examples
The following examples show typical syntax characters used in SKILL.
Example 1
list( g_arg1 [ g_arg2 ] ... ) => l_result
This example illustrates the following syntax characters.
list Plain type indicates words that you must enter literally.
g_arg1 Words in italics indicate arguments for which you must substitute
a name or a value.
( ) Parentheses separate names of functions from their arguments.
_ An underscore separates an argument type (left) from an
argument name (right).
[ ] Brackets indicate that the enclosed argument is optional.
... Three dots indicate that the preceding item can appear any
number of times.
=> A right arrow points to the description of the return value of the
function. Also used in code examples in SKILL manuals.
l_result All SKILL functions compute a data value known as the return
value of the function.
Example 2
needNCells( s_cellType | st_userType x_cellCount ) => t / nil
This example illustrates two additional syntax characters.
| Vertical bars separate a choice of required options.
/ Slashes separate possible return values.
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SKILL Language Functions
Cadence
®
SKILL is a high-level, interactive programming language based on the popular
artificial intelligence language,
Lisp.
This chapter describes the following:
■ Functions that are common to all of the Cadence tools used in either a graphic or
nongraphic environment. For information about using these functions, see the
SKILL
Language User Guide.
■ SKILL++ core functions. SKILL++ is the second generation extension language for
Cadence software. SKILL++ combines the ease-of-use of the SKILL environment with
the power of the Scheme programming language. The major power brought in from
Scheme is its use of lexical scoping and functions with lexically-closed environments
called closures.
■ Arithmetic and logical operators. All arithmetic operators are translated into calls to
predefined SKILL functions. These operators are listed in
Chapter 5, “Arithmetic and
Logical Expressions” in the SKILL Language User Guide.
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abs
abs(
n_number
)
=> n_result
Description
Returns the absolute value of a floating-point number or integer.
Arguments
n_number Floating-point number or integer.
Value Returned
n_result Absolute value of n_number.
Example
abs( -209.625)
=> 209.625
abs( -23)
=> 23
Reference
min
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acos
acos(
n_number
)
=> f_result
Description
Returns the arc cosine of a floating-point number or integer.
Arguments
n_number Floating-point number or integer.
Value Returned
f_result Arc cosine of n_number.
Example
acos(0.3)
=> 1.266104
Reference
cos
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add1
add1(
n_number
)
=> n_result
Description
Adds one to a floating-point number or integer.
Arguments
n_number Floating-point number or integer to increase by one.
Value Returned
n_result n_number plus one.
Example
add1( 59 )
=> 60
Reference
sub1
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addDefstructClass
addDefstructClass(
s_name
)
=> u_classObject
Description
Creates a class for the defstruct.
By default, an instance of a defstruct does not have class. You cannot use
makeInstance to instantiate this class. Use the instantiation function created by
defstruct.
Using addDefstructClass to create a class for a defstruct, allows you to define
methods for a defstruct.
Arguments
s_name The name of the defstruct
Value Returned
u_classObject The class object
Example
defstruct( card rank suit ) => t
x = make_card( ?rank 8 ?suit "spades" )
=> array[4]:3897312
type( x ) => card
findClass( 'card ) => nil
classOf( x ) => nil
addDefstructClass( card ) => funobj:0x1c98f8
className( classOf( x )) => card
Reference
defstruct, makeInstance
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alias
alias(
s_aliasName
s_functionName
)
=> s_aliasName
Description
Defines a symbol as an alias for a function. This is an nlambda function.
Defines the s_aliasName symbol as an alias for the s_functionName function, which
must already have been defined. The alias function does not evaluate its arguments.
Caution
Use alias only to speed up interactive command entry and never in
programs.
Arguments
s_aliasName Symbol name of the alias.
s_functionName Name of the function you are creating an alias for.
Value Returned
s_aliasName Name of the alias.
Example
alias path getSkillPath => path
Aliases path to the getSkillPath function.
alias e edit => e
Aliases e to the edit function.
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alphalessp
alphalessp(
S_arg1
S_arg2
)
=> t | nil
Description
Compares two string or symbol names alphabetically.
This function returns t if the first argument is alphabetically less than the second argument.
If S_arg is a symbol, then its name is its print name. If S_arg is a string, then its name is
the string itself.
Arguments
S_arg1 First name you want to compare.
S_arg2 Name to compare against.
Value Returned
t If S_arg1 is alphabetically less than the name of S_arg2.
nil In all other cases.
Example
alphalessp( "name" "name1" ) => t
alphalessp( "third" "fourth" ) => nil
alphalessp('a 'ab) => t
Reference
strcmp, strncmp
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alphaNumCmp
alphaNumCmp(
S_arg1
S_arg2
[ g_arg3 ]
)
=> 1 | 0 | -1
Description
Compares two string or symbol names alphanumerically or numerically.
If the third optional argument is non-nil and the first two arguments are strings holding
purely numeric values, then a numeric comparison is performed on the numeric
representation of the strings.
Arguments
S_arg1 First string or symbol to compare.
S_arg2 String or symbol to compare against S_arg1.
g_arg3 If non-nil, can cause a numeric comparison of S_arg1 and
S_arg2 depending whether those arguments are strings
holding purely numeric values.
Value Returned
1 If S_arg1 is alphanumerically greater than S_arg2
0 If S_arg1 is alphanumerically identical to S_arg2.
-1 If S_arg2 is alphanumerically greater than S_arg1.
Example
alphaNumCmp( "a" "b" ) => -1
alphaNumCmp( "b" "a" ) => 1
alphaNumCmp( "name12" "name12" ) => 0
alphaNumCmp( "name23" "name12" ) => 1
alphaNumCmp( "00.09" "9.0E-2" t) => 0
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and
and(
g_arg1
g_arg2
[ g_arg3... ]
)
=> nil | g_val
Description
Evaluates from left to right its arguments to see if the result is nil. As soon as an argument
evaluates to nil, and returns nil without evaluating the rest of the arguments. Otherwise,
and evaluates the next argument. If all arguments except for the last evaluate to non-nil,
and returns the value of the last argument as the result of the function call. Prefix form of the
&& binary operator.
Arguments
g_arg1 Any SKILL object.
g_arg2 Any SKILL object.
g_arg3 Any SKILL object.
Value Returned
nil If an argument evaluates to nil.
g_val Value of the last argument if all the preceding arguments
evaluate to non-nil.
Example
and(nil t) => nil
and(t nil) => nil
and(18 12) => 12
Reference
band, bnand, bnor, bnot, bor, bxnor, bxor, not
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append
append(
l_list1
l_list2
)
=> l_result
append(
o_table
g_assoc
)
=> o_table
Description
Creates a list containing the elements of l_list1 followed by the elements of l_list2 or
returns the original association table including new entries.
The top-level list cells of l_list1 are duplicated and the cdr of the last duplicated list cell
is set to point to l_list2; therefore, this is a time-consuming operation if l_list1 is a
long list.
Note: This is a slow operation and the functions tconc, lconc, and nconc can be used
instead for adding an element or a list to the end of a list. The command cons is even better
if the new list elements can be added to the beginning of the list.
The append function can also be used with association tables as shown in the second syntax
statement. Key/value pairs are added to the original association table (not to a copy of the
table). This function should be used mainly in converting existing association lists or
disembodied property lists to an association table. See “
Association Table“ in the SKILL
Language User Guide for more details.
Arguments
l_list1 List of elements to be added to a list.
l_list2 List of elements to be added.
o_table Association table to be updated.
g_assoc Key/value pairs to be added to the association table.
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Value Returned
l_result Returns a list containing elements of l_list1 followed by
elements of l_list2.
o_table Returns the original association table including the new entries.
Example
/* List Example */
append( '(1 2) '(3 4) )
=> (1 2 3 4)
/* Association Table Example */
myTable = makeTable("myAssocTable")
=> table:myAssocTable
myTable['a] = 1
=> 1
append(myTable '((b 2) (c 3)))
=> table:myAssocTable
/* Check the contents of the assoc table */
tableToList(myTable)
=> ((a 1) (b 2) (c 3))
Reference
tconc, lconc, nconc, append1, cons
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append1
append1(
l_list
g_arg
)
=> l_result
Description
Adds new arguments to the end of a list.
Returns a list just like l_list with g_arg added as the last element of the list.
Note: This is a slow operation and the functions tconc, lconc, and nconc can be used
instead for adding an element or a list to the end of a list. The command cons is even better
if the new list elements can be added to the beginning of the list.
Arguments
l_list List to which g_arg is added.
g_arg Argument to be added to the end of l_list.
Value Returned
l_result Returns a copy of l_list with g_arg attached to the end.
Example
append1('(1 2 3) 4) => (1 2 3 4)
Like append, append1 duplicates the top-level list cells of l_list.
Reference
append
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apply
apply(
slu_func
l_args
)
=> g_result
Description
Applies the given function to the given argument list.
The first argument to apply must be either the name of a function or a list containing a
lambda/nlambda/macro expression or a function object. The second argument is a list of
arguments to be passed to the function.
The argument list l_args is bound to the formal arguments of slu_func according to the
type of function. For lambda functions the length of l_args should match the number of
formal arguments, unless keywords or optional arguments exist. For nlambda and macro
functions, l_args is bound directly to the single formal parameter of the function.
Note: If slu_func is a macro, apply evaluates it only once, that is, it expands it and
returns the expanded form, but does not evaluate the expanded form again (as eval does).
Arguments
slu_func Name of the function.
l_args Argument list to apply to the function.
Value Returned
g_result Returns the result of applying the function to the given
arguments.
Example
apply('plus (list 1 2) ) ; Apply plus to its arguments.
=> 3
procedure( sumTail(l) apply( 'plus cdr(l)))
=> sumTail ;Define a procedure
sumTail( '(1 2 3))
=> 5
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argc
argc(
)
=> n | 0 | -1 | -2
Description
Returns the number of arguments passed to a SKILL script. Used to enhance the SKILL
script environment.
Value Returned
nnarguments were passed (n is an integer).
0 No arguments were passed, but argv(0) has a value.
-1 Argument list is nil (no arguments passed, and argv(0) is
nil). This can occur when using SKILL interactively.
-2 Error caused by a problem with the argument list property.
Example
Assume that arguments passed to a SKILL script file are ("my.il""1st""2nd""3rd"):
argc() => 3
Reference
argv
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argv
argv(
[ x_int ]
)
=> g_result
Description
Returns the arguments passed to a SKILL script. Used to enhance the SKILL script
environment.
Arguments
x_int Optional argument; it must be a positive integer.
Value Returned
g_result The return value depends on the arguments passed.
.
Example
Assume that arguments passed to a SKILL script file are (“my.il” “1st” “2nd”
“3rd”):
argv() => (“1st” “2nd” “3rd”)
argv(0) => “my.il”
argv(1) => “1st”
argv(4) => nil
Reference
argc
Argument Returned
argv( ) List of all arguments (list of strings or nil).
argv(0) Name of the calling script.
argv(n) nth argument as a string or nil if there is no nth argument.
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arrayp
arrayp(
g_value
)
=> t | nil
Description
Checks if an object is an array.
The suffix pis usually added to the name of a function to indicate that it is a predicate function.
Arguments
g_value Any data object.
Value Returned
t If g_value is an array object.
nil Otherwise.
Example
declare(x[10])
arrayp(x) => t
arrayp('x) => nil
Reference
declare
SKILL Language Reference
SKILL Language Functions
August 2005 44 Product Version 06.40
arrayref
arrayref(
g_collection
g_index
)
=> g_element
Description
Returns the element in a collection that is in an array or a table of the given index.
This function is usually called implicitly using the [ ] syntax.
Arguments
g_collection An array or a table.
g_index An integer for indexing an array. An arbitrary object for indexing
a table.
Value Returned
g_element The element selected by the given index in the given collection.
Example
a[3]
=> 100 ;if the fourth element of the array is 100
(arrayref a 3 )
=> 100 ;same as a[3]
Reference
The syntax a[i] = b, referred to as the setarray function.
SKILL Language Reference
SKILL Language Functions
August 2005 45 Product Version 06.40
asin
asin(
n_number
)
=> f_result
Description
Returns the arc sine of a floating-point number or integer.
Arguments
n_number Floating-point number or integer.
Value Returned
f_result Arc sine of the value passed in.
Example
asin(0.3) => 0.3046927
Reference
sin
SKILL Language Reference
SKILL Language Functions
August 2005 46 Product Version 06.40
assoc, assq, assv
assv(
g_key
l_alist
)
=> l_association | nil
Description
The assoc, assq, and assv functions find the first list in l_alist whose car field is g_key
and return that list. assq uses eq to compare g_key with the car fields of the lists in alist.
assoc uses equal. assv uses eqv.
The association list, l_alist, must be a list of lists. An association list is a standard data
structure that has the form ((key1 value1) (key2 value2) (key3 value3) ...).
These functions find the first list in l_alist whose car field is g_key and return that list.
assquses eq to compare g_key with the car fields of the lists in l_alist. assvuses eqv.
assoc uses equal.
Arguments
g_key An arbitrary object as the search key.
l_alist Association list. Must be a list of lists.
Value Returned
l_association The returned list is always an element of l_alist.
nil If no list in l_alist has g_key, as its car.
Example
e = '((a 1) (b 2) (c 3))
(assq 'a e) => (a 1)
(assq 'b e) => (b 2)
(assq 'd e) => nil
(assq (list 'a) '(((a)) ((b)) ((c)))) => nil
(assoc (list 'a) '(((a)) ((b)) ((c)))) => ((a))
(assv 5 '((2 3) (5 7) (11 13))) => (5 7)
SKILL Language Reference
SKILL Language Functions
August 2005 48 Product Version 06.40
atan
atan(
n_number
)
=> f_result
Description
Returns the arc tangent of a floating-point number or integer.
Arguments
n_number Floating-point number or integer.
Value Returned
f_result Arc tangent of n_number.
Example
atan(0.3) => 0.2914568
Reference
tan
SKILL Language Reference
SKILL Language Functions
August 2005 49 Product Version 06.40
atof
atof(
t_string
)
=> f_result | nil
Description
Converts a string into a floating-point number. Returns nil if the given string does not denote
a number.
The atof function calls the C library function strtod to convert a string into a floating-point
number. It returns nil if t_string does not represent a number.
Arguments
t_string A string.
Value Returned
f_result The floating-point value represented by t_string.
nil If t_string does not denote a floating-point number.
Example
atof("123") => 123.0
atof("abc") => nil
atof("123.456") => 123.456
atof("123abc") => 123.0
Reference
atoi
SKILL Language Reference
SKILL Language Functions
August 2005 50 Product Version 06.40
atoi
atoi(
t_string
)
=> x_result | nil
Description
Converts a string into an integer. Returns nil if the given string does not denote an integer.
The atoi function calls the C library function strtol to convert a string into an integer. It
returns nil if t_string does not represent an integer.
Arguments
t_string A string.
Value Returned
x_result The integer value represented by t_string.
nil If t_string does not denote an integer.
Example
atoi("123") => 123
atoi("abc") => nil
atoi("123.456") => 123
atoi("123abc") => 123
Reference
atof
SKILL Language Reference
SKILL Language Functions
August 2005 51 Product Version 06.40
atom
atom(
g_arg
)
=> t | nil
Description
Checks if an object is an atom.
Atoms are all SKILL objects except non-empty lists. The special symbol nil is both an atom
and a list.
Arguments
g_arg Any SKILL object.
Value Returned
t If g_arg is an atom.
nil If g_arg is not an atom.
Example
atom( 'hello ) => t
x = '(a b c)
atom( x ) => nil
atom( nil ) => t
Reference
dtpr, listp
SKILL Language Reference
SKILL Language Functions
August 2005 52 Product Version 06.40
band
band(
x_op1
x_op2
[ x_op3 ... ]
)
=> x_result
Description
Returns the integer result of the Boolean AND operation on each parallel pair of bits in each
operand. Prefix form of the & bitwise operator.
Arguments
x_op1 Operand to be evaluated.
x_op2 Operand to be evaluated.
x_op3 Optional additional operands to be evaluated.
Value Returned
x_result Result of the operation.
Example
band(12 13) => 12
band(1 2 3 4 5) => 0
Reference
and, bnand, bnor, bnot, bor, bxnor, bxor, not
SKILL Language Reference
SKILL Language Functions
August 2005 53 Product Version 06.40
bcdp
bcdp(
g_value
)
=> t | nil
Description
Checks if an object is a binary primitive function.
The suffix pis usually added to the name of a function to indicate that it is a predicate function.
Arguments
g_value Object to check.
Value Returned
t If g_value is a binary function.
nil Otherwise.
Example
bcdp(getd('plus)) => t
bcdp('plus) => nil
Reference
getd
SKILL Language Reference
SKILL Language Functions
August 2005 54 Product Version 06.40
begin - SKILL mode
begin(
g_exp1
[ g_exp2 ...
g_expN ]
)
=> g_result
Description
In SKILL mode begin is a syntax form used to group a sequence of expressions. Evaluates
expressions from left to right and returns the value of the last expression. Equivalent to
progn.
This expression type is used to sequence side effects such as input and output.
Arguments
g_exp1, g_exp2, g_expN
Arbitrary expressions.
Value Returned
g_result Value of the last expression, g_expN.
Example
begin( x = 1 y = 2 z = 3 )
=> 3
Reference
progn
SKILL Language Reference
SKILL Language Functions
August 2005 55 Product Version 06.40
begin - SKILL++ mode
begin(
def1
[ def2 ...
defN ]
)
=> g_result
begin(
exp1
[ exp2 ...
expN ]
)
=> g_result
Description
In SKILL++ mode begin is a syntax form used to group either a sequence of expressions or
a sequence of definitions.
begin( exp1 [exp2 ... expN] )
The expressions are evaluated sequentially from left to right, and the value of the last
expression is returned. This expression type is used to sequence side effects such as input
and output.
begin( [def1 def2 ... defN] )
This form is treated as though the set of definitions is given directly in the enclosing context.
It is most commonly found in macro definitions.
Value Returned
g_result Value of the last expression or definition.
Example
begin( x = 1 y = 2 z = 3 ) => 3
begin( define( x 1 ) define( y 2 ) define( z 3 ) ) => z
Reference
define - SKILL++ mode
SKILL Language Reference
SKILL Language Functions
August 2005 56 Product Version 06.40
bitfield1
bitfield1(
x_val
x_bitPosition
)
=> x_result
Description
Returns the value of a specified bit of a specified integer. Prefix form of the <> operator.
Arguments
x_val Integer for which you want to extract the value of a specified bit.
x_bitPosition Position of the bit whose value you want to extract.
Value Returned
x_result Value of a single bit.
Example
x = 0b1001
bitfield1(x 0) => 1
bitfield1(x 3) => 1
Reference
bitfield, setqbitfield1, setqbitfield
SKILL Language Reference
SKILL Language Functions
August 2005 57 Product Version 06.40
bitfield
bitfield(
x_val
x_msb
x_lsb
)
=> x_result
Description
Returns the value of a specified set of bits of a specified integer. Prefix form of the <:>
operator.
Arguments
x_val Integer for which you want to extract the value of a specified set
of bits.
x_msb Leftmost bit of the set of bits to be extracted.
x_lsb Rightmost bit of the set of bits to be extracted.
Value Returned
x_result Value of the set of bits.
Example
x = 0b1011
bitfield(x 2 0) => 3
bitfield(x 3 0) => 11
Reference
bitfield1, setqbitfield1, setqbitfield
SKILL Language Reference
SKILL Language Functions
August 2005 58 Product Version 06.40
blankstrp
blankstrp(
t_string
)
=> t | nil
Description
Checks if the given string is empty or has blank space characters only and returns true. If
there are non-space characters blankstrp returns nil.
Arguments
t_string A string.
Value Returned
t If t_string is blanks or is an empty string.
nil If there are non-space characters.
Example
blankstrp( "")
t
blankstrp( " ")
t
blankstrp( "a string")
nil
SKILL Language Reference
SKILL Language Functions
August 2005 59 Product Version 06.40
bnand
bnand(
x_op1
x_op2
[ x_op3 ... ]
)
=> x_result
Description
Returns the integer result of the Boolean NAND operation on each parallel pair of bits in each
operand. Prefix form of the ~& bitwise operator.
Arguments
x_op1 Operand to be evaluated.
x_op2 Operand to be evaluated.
x_op3 Optional additional operands to be evaluated.
Value Returned
x_result Result of the operation.
Example
bnand(12 13) => -13
bnand(1 2 3 4 5) => -1
Reference
and, band, bnor, bnot, bor, bxnor, bxor, not
SKILL Language Reference
SKILL Language Functions
August 2005 60 Product Version 06.40
bnor
bnor(
x_op1
x_op2
[ x_op3 ... ]
)
=> x_result
Description
Returns the integer result of the Boolean NOR operation on each parallel pair of bits in each
operand. Prefix form of the ~| bitwise operator.
Arguments
x_op1 Operand to be evaluated.
x_op2 Operand to be evaluated.
x_op3 Optional additional operands to be evaluated.
Value Returned
x_result Result of the operation.
Example
bnor(12 13) => -14
bnor(1 2 3 4 5) => -8
Reference
and, band, bnand, bnot, bor, bxnor, bxor, not
SKILL Language Reference
SKILL Language Functions
August 2005 61 Product Version 06.40
bnot
bnot(
x_op
)
=> x_result
Description
Returns the integer result of the Boolean NOT operation on each parallel pair of bits in each
operand. Prefix form of the ~ (one’s complement) unary operator.
Arguments
x_op Operand to be evaluated.
Value Returned
x_result Result of the operation.
Example
bnot(12) => -13
bnot(-12) => 11
Reference
and, band, bnand, bnor, bor, bxnor, bxor, not
SKILL Language Reference
SKILL Language Functions
August 2005 62 Product Version 06.40
booleanp
booleanp(
g_obj
)
=> t | nil
Description
Checks if an object is a boolean. Returns t if the object is t or nil. Returns nil otherwise.
Arguments
g_obj Any SKILL object.
Value Returned
t If g_obj is either t or nil.
nil Otherwise.
Example
(booleanp 0 ) => nil
(booleanp nil) => t
(booleanp t) => t
SKILL Language Reference
SKILL Language Functions
August 2005 63 Product Version 06.40
bor
bor(
x_op1
x_op2
[ x_op3 ... ]
)
=> x_result
Description
Returns the integer result of the Boolean OR operation on each parallel pair of bits in each
operand. Prefix form of the | bitwise operator.
Arguments
x_op1 Operand to be evaluated.
x_op2 Operand to be evaluated.
x_op3 Optional additional operands to be evaluated.
Value Returned
x_result Result of the operation.
Example
bor(12 13) => 13
bor(1 2 3 4 5) => 7
Reference
and, band, bnand, bnor, bnot, bxnor, bxor, not
SKILL Language Reference
SKILL Language Functions
August 2005 64 Product Version 06.40
boundp
boundp(
s_arg
[ e_environment ]
)
=> t | nil
Description
Checks if the variable named by a symbol is bound, that is, has been assigned a value. The
single argument form of boundp only works in SKILL mode.
Remember that a variable can be set to the special symbol unbound.
Note: The single argument form of boundp only works in SKILL mode.
Arguments
s_arg Symbol to be tested to see if it is bound.
e_environment If this argument is given, SKILL++ semantics are used. The
symbol will be searched for within the given (lexical)
environment.
Value Returned
t If the symbol s_arg has been assigned a value.
nil If the symbol s_arg has not been assigned a value.
Example
x = 5 ; Binds x to the value 5.
y = 'unbound ; Unbind y
boundp( 'x )
=> t
boundp( 'y )
=> nil
SKILL Language Reference
SKILL Language Functions
August 2005 65 Product Version 06.40
y = 'x ; Bind y to the constant x.
boundp( y )
=> t ; Returns t because y evaluates to x,
; which is bound.
SKILL Language Reference
SKILL Language Functions
August 2005 66 Product Version 06.40
buildString
buildString(
l_strings
[ S_glueCharacters ]
)
=> t_string
Description
Concatenates a list of strings with specified separation characters.
Arguments
l_strings List of strings. A null string is permitted.
S_glueCharacters Separation characters you use within the strings. A null string is
permitted. If this argument is omitted, the default single space is
used.
Value Returned
t_string Strings concatenated with t_glueCharacters. Signals an
error if l_strings is not a list of strings.
Example
buildString( '("test" "il") ".") => "test.il"
buildString( '("usr" "mnt") "/") => "usr/mnt"
buildString( '("a" "b" "c")) => "a b c"
buildString( '("a" "b" "c") "") => "abc"
buildString( '("A" "B") 'and) => "AandB"
Reference
parseString
SKILL Language Reference
SKILL Language Functions
August 2005 67 Product Version 06.40
bxnor
bxnor(
x_op1
x_op2
[ x_op3 ... ]
)
=> x_result
Description
Returns the integer result of the Boolean XNOR operation on each parallel pair of bits in each
operand. Prefix form of the ~^ bitwise operator.
Arguments
x_op1 Operand to be evaluated.
x_op2 Operand to be evaluated.
x_op3 Optional additional operands to be evaluated.
Value Returned
x_result Result of the operation.
Example
bxnor(12 13) => -2
bxnor(1 2 3 4 5) => -2
Reference
and, band, bnand, bnor, bnot, bor, bxor, not
SKILL Language Reference
SKILL Language Functions
August 2005 68 Product Version 06.40
bxor
bxor(
x_op1
x_op2
[ x_op3 ... ]
)
=> x_result
Description
Returns the integer result of the Boolean XOR operation on each parallel pair of bits in each
operand. Prefix form of the ^ bitwise operator.
Arguments
x_op1 Operand to be evaluated.
x_op2 Operand to be evaluated.
x_op3 Optional additional operands to be evaluated.
Value Returned
x_result Result of the operation.
Example
bxor(12 13) => 1
bxor(1 2 3 4 5) => 1
Reference
and, band, bnand, bnor, bnot, bor, bxnor, not
SKILL Language Reference
SKILL Language Functions
August 2005 69 Product Version 06.40
caar, caaar, caadr, cadr, caddr, cdar, cddr, ...
ca|d[ a|d ][ a|d ][ a|d ]r(
l_list
)
=> g_result
Description
Performs operations on a list using repeated applications of car and cdr. For example,
caaar is equivalent to car( car( car( l_list))). The possible combinations are
caaaar, caaadr, caadar, caaddr, caar, caddar, cadddr, cadr, cdaaar, cdaadr, cdaar, cdadar,
cdaddr, cdadr, cdar, cddaar, cddadr, cddar, cdddar, cddddr, cdddr, cddr, caaar, caadr, cadar,
caddr, cdadr, cadaar, cadadr, caddar, cadddr, cdaaar, cdaadr, cdadar, cdaddr, cddaar,
cddadr, cdddar, and cddddr.
The cadr(l_list) expression, for example, applies cdr to get the tail of the list and then
applies car to get the first element of the tail, in effect extracting the second element from the
list. SKILL implements all c...r functions with any combination of a and d up to four
characters.
Arguments
l_list List of elements.
Value Returned
g_result Returns the value of the specified operation.
Example
caaar('(((1 2 3)(4 5 6))(7 8 9))) => 1
caaar is equivalent to car( car( car( l_list))).
caadr('(((1 2 3)(4 5 6))(7 8 9))) => 7
Equivalent to car( car( cdr( l_list))).
caar('(((1 2 3)(4 5 6))(7 8 9))) => (1 2 3)
Equivalent to car( car( l_list)).
SKILL Language Reference
SKILL Language Functions
August 2005 71 Product Version 06.40
car
car(
l_list
)
=> g_result
Description
Returns the first element of a list. car is nondestructive, meaning that it returns the first
element of a list but does not actually modify the list that was its argument.
The functions car and cdrare typically used to take a list of objects apart, whereas the cons
function is usually used to build up a list of objects. car was a machine language instruction
on the first machine to run Lisp. car stands for contents of the address register.
Arguments
l_list A list of elements.
Value Returned
g_result Returns the first element in a list. Note that car(nil) returns
nil.
Example
car( '(a b c) ) => a
z = '(1 2 3) => (1 2 3)
y = car(z) => 1
y => 1
z => (1 2 3)
car(nil) => nil
Reference
cdr, cons
SKILL Language Reference
SKILL Language Functions
August 2005 72 Product Version 06.40
case, caseq
case(
g_selectionExpr
l_clause1
[ l_clause2 ... ]
)
=> g_result | nil
Description
Evaluates the selection expression, matches the resulting selector values sequentially
against comparators defined in clauses, and executes the expressions in the matching
clause. This is a syntax function.
Each l_clause is a list of the form (g_comparator g_expr1 [g_expr2 ...] ),
where a comparator is either an atom (that is, a scalar) of any data type or a list of atoms.
Comparators are always treated as constants and are never evaluated. The
g_selectionExpr is evaluated and the resulting selector value is matched sequentially
against comparators defined in l_clause1, l_clause2, ... and so on. A match occurs
when either the selector is equal to the comparator or the selector is equal to one of the
elements in the list given as the comparator. If a match is found, the expressions in that clause
and that clause only (that is, the first match) are executed. The value of caseis then the value
of the last expression evaluated (that is, the last expression in the clause selected). If there
is no match, case returns nil.
The symbol t has special meaning as a comparator in that it matches anything. It is typically
used in the last clause to serve as a default case when no match is found with other clauses.
Comparing case with caseq
caseq is a considerably faster version of case. caseq uses the function eq rather than
equal for comparison. The comparators for caseq are therefore restricted to being either
symbols or small integer constants (-256 <= i <= 255), or lists containing symbols and
small integer constants.
Arguments
g_selectionExpr An expression whose value is evaluated and tested for equality
against the comparators in each clause. When a match is found
the rest of the clause is evaluated.
SKILL Language Reference
SKILL Language Functions
August 2005 73 Product Version 06.40
l_clause1 An expression whose first element is an atom or list of atoms to
be compared against the value of g_selectionExpr. The
remainder of the l_clause is evaluated if a match is found.
l_clause2 Zero or more clauses of the same form as l_clause1.
Value Returned
g_result Returns the value of the last expression evaluated in the
matched clause, or nil if there is no match.
nil If there is no match.
Example
nameofmonth = "February"
month = case( nameofmonth
("January" 1)
("February" 2)
(t 'Other))
=> 2
procedure( testCase( selector )
caseq(selector
(0 println("selector is 0"))
(1 println("selector is 1"))
((2 3) println("selector is either 2 or 3"))
((a b) println("selector is either the symbol a or b"))
(t println("selector is none of the above"))
))
testCase( 1 )
=> testCase
"selector is 1" ; Printed by caseq statement.
=> nil ; Value returned by println.
testCase( 'b )
"selector is either the symbol a or b" ; Printed by caseq.
=> nil ; Value returned by println.
Reference
eq, equal
SKILL Language Reference
SKILL Language Functions
August 2005 74 Product Version 06.40
cdr
cdr(
l_list
)
=> l_result
Description
Returns the tail of the list, that is, the list without its first element.
The expression cdr(nil) returns nil. cdrwas a machine language instruction on the first
machine to run Lisp. cdr stands for contents of the decrement register.
Arguments
l_list List of elements.
Value Returned
l_result Returns the end of a list, or the list minus the first element.
Example
cdr( '(a b c) ) => (b c)
z = '(1 2 3)
cdr(z) => (2 3)
Note: cdr always returns a list, so cdr('(2 3)) returns the list (3) rather than the
integer 3.
Reference
caar, caaar, caadr, cadr, caddr, cdar, cddr, ...
SKILL Language Reference
SKILL Language Functions
August 2005 75 Product Version 06.40
cdsGetInstPath
cdsGetInstPath(
[ t_name ]
)
=> t_string
Description
Returns the absolute path of the Cadence installation directory as a string.
cdsGetInstPath is for the cds root hierarchy and is meant to be used by all DFII and non-
DFII applications.
Arguments
t_name The optional argument t_name is appended to the end of the
cds root path with a directory separator if necessary.
Value Returned
t_string Returns the installation path as a string.
Example
cdsGetInstPath() => "/cds/99.02/latest.il"
cdsGetInstPath("tools") =>"/cds/99.02/latest.il/tools"
Reference
getInstallPath, getSkillPath, getWorkingDir, prependInstallPath
SKILL Language Reference
SKILL Language Functions
August 2005 76 Product Version 06.40
ceiling
ceiling(
n_number
)
=> x_integer
Description
Returns the smallest integer not smaller than the given argument.
Arguments
n_number Any number.
Value Returned
x_integer Smallest integer not smaller than n_number.
Example
(ceiling -4.3) => -4
(ceiling 3.5) => 4
Reference
floor, round, truncate
SKILL Language Reference
SKILL Language Functions
August 2005 77 Product Version 06.40
changeWorkingDir
changeWorkingDir(
[ S_name ]
)
=> t
Description
Changes the working directory to S_name.
Different error messages are printed if the operation fails because the directory does not exist
or you do not have search (execute) permission.
Caution
Use this function with care: if “.” is either part of the SKILL path or the
libraryPath, changing the working directory can affect the visibility of
SKILL files or design data.
Arguments
S_name Name of the working directory you want to use. Can be specified
with either a relative or absolute path. If you supply a relative
path, the shell environment is used to search for the directory, not
the SKILL path.
Value Returned
t Returns t if the function executes successfully. Prints an error
message if the directory you tried to change to does not exist.
Prints a permission denied message if you do not have search
permission.
Example
Assume there is a directory /usr5/design/cpu with proper permission and there is no
test directory under /usr5/design/cpu.
changeWorkingDir( "/usr5/design/cpu") => t
changeWorkingDir( "test")
SKILL Language Reference
SKILL Language Functions
August 2005 79 Product Version 06.40
charToInt
charToInt(
s_char
)
=> x_ascii
Description
Returns the ASCII code of the first character of the given symbol. In SKILL, a single character
symbol can be used as a character value.
Arguments
s_char A symbol.
Value Returned
x_ascii The ASCII code of the (first) character of the given symbol.
Example
charToInt('B)
=> 66
charToInt('Before)
=> 66
Reference
intToChar
SKILL Language Reference
SKILL Language Functions
August 2005 80 Product Version 06.40
clearExitProcs
clearExitProcs(
)
=> t
Description
Removes all registered exit functions (takes no arguments).
Arguments
None.
Value Returned
t Always returns t.
Example
clearExitProcs( )=> t
Reference
exit, regExitBefore, regExitAfter, remExitProc
SKILL Language Reference
SKILL Language Functions
August 2005 81 Product Version 06.40
close
close(
p_port
)
=> t
Description
Drains, closes, and frees a port.
When a file is closed, it frees the FILE* associated with p_port. Do not use this function
on piport, poport, stdin, stdout, and stderr.
Arguments
p_port Name of port to close.
Value Returned
t Returns t if the port is closed successfully.
Example
p = outfile("~/test/myFile") => port:"~/test/myFile"
close(p) => t
Reference
outfile, infile, drain
SKILL Language Reference
SKILL Language Functions
August 2005 82 Product Version 06.40
compareTime
compareTime(
t_time1
t_time2
)
=> x_difference
Description
Compares two string arguments, representing a clock-calendar time.
Arguments
t_time1 First string in the month day hour:minute:second
year format.
t_time2 Second string in the month day hour:minute:second
year format.
Value Returned
x_difference An integer representing a time that is later than (positive), equal
to (zero), or earlier than (negative) the second argument. The
units are seconds.
Example
compareTime( "Apr 8 4:21:39 1991" "Apr 16 3:24:36 1991")
=> -687777.
687,777 seconds have occurred between the two dates given. For a positive number of
seconds, the most recent date needs to be given as the first argument.
compareTime("Apr 16 3:24:36 1991" "Apr 16 3:14:36 1991")
=> 600
600 seconds (10 minutes) have occurred between the two dates.
Reference
getCurrentTime
SKILL Language Reference
SKILL Language Functions
August 2005 83 Product Version 06.40
compress
compress(
t_sourceFile
t_destFile
)
=> t | error message
Description
Reduces the size of a SKILL file, which must be SKILL source code, and places the output
into another file.
Compression renders the data less readable because indentation and comments are lost. It
is not the same as encrypting the file because the representation of t_destFile is still in
ASCII format. This process does not remove the source file.
Arguments
t_sourceFile Name of the SKILL source file.
t_destFile Name of the destination file.
Value Returned
t Returns t when function executes successfully.
error message Signals an error if problems are encountered compressing the
file.
Example
compress( "triad.il" "triad_cmp.il") => t
Reference
encrypt
SKILL Language Reference
SKILL Language Functions
August 2005 84 Product Version 06.40
concat
concat(
Sx_arg1
[ Sx_arg2 ... ]
)
=> s_result
Description
Concatenates strings, symbols, or integers into a single symbol.
This function is useful for converting strings to symbols. To concatenate several strings and
have a single string returned, use the strcat function. Symbol names are limited to 255
characters.
Symbol functions such as eq, memq, and caseq are much faster than their siblings equal,
member, and case because they compare pointers rather than data. You can use concat to
convert a string to a symbol before performing memq on large lists for increased speed.
Arguments
Sx_arg1 String, symbol, or integer to be concatenated.
Sx_arg2 Zero or more strings, symbols, or integers to be concatenated.
Value Returned
s_result Returns a symbol whose print name is the result of
concatenating the printed representation of the argument or
arguments.
Example
concat("string") => string
concat("ab" 123 'xy) => ab123xy
memq( concat( "c" ) '(a b c d e)) => (c d e)
This demonstrates using concat to take advantage of the faster functions such as memq.
SKILL Language Reference
SKILL Language Functions
August 2005 86 Product Version 06.40
cond
cond(
l_clause1 ...
)
=> g_result
Description
Examines conditional clauses from left to right until either a clause is satisfied or there are no
more clauses remaining. This is a syntax function.
Each clause has the form ( g_condition g_expr1 ... ). cond examines a clause
by evaluating the condition associated with the clause. The clause is said to be “satisfied” if
g_condition evaluates to non-nil, in which case expressions in the rest of the clause
are evaluated from left to right, and the value returned by the last expression in the clause is
returned as the value of the cond form. If g_condition evaluates to nil, however, cond
skips the rest of the clause and moves on to the next clause.
Arguments
l_clause1 Each clause should be of the form (g_condition g_expr1
...) where if g_condition evaluates to non-nilthen all the
succeeding expressions are evaluated.
Value Returned
g_result Value of the last expression of the satisfied clause, or nil if no
clause is satisfied.
Example
procedure( test(x)
cond(((null x) (println "Arg is null"))
((numberp x)(println "Arg is a number"))
((stringp x)(println "Arg is a string"))
(t (println "Arg is an unknown type"))))
test( nil ) => nil; Prints "Arg is null".
test( 5 ) => nil; Prints "Arg is a number".
test( 'sym ) => nil; Prints "Arg is an unknown type".
SKILL Language Reference
SKILL Language Functions
August 2005 87 Product Version 06.40
cons
cons(
g_element
l_list
)
=> l_result
Description
Adds an element to the beginning of a list.
Thus the car of l_result is g_element and the cdr of l_result is l_list.
l_list can be nil, in which case a new list containing the single element is created.
Arguments
g_element Element to be added to the beginning of l_list.
l_list List that can be nil.
Value Returned
l_result List whose first element is g_element and whose cdr is
l_list.
Example
cons(1 nil) => (1)
cons( 'a '(b c)) => (a b c)
The following example shows how to efficiently build a list from 1 to 100. You can reverse the
list if necessary.
x = nil
for( i 1 100 x = cons( i x )) => t
x => (100 99 98 .. 2 1)
x = reverse( x ) => (1 2 3 .. 100)
Reference
car, cdr, append, append1
SKILL Language Reference
SKILL Language Functions
August 2005 88 Product Version 06.40
constar
constar(
[ g_arg1 ... ]
l_list
)
=> l_result
Description
Adds elements to the beginning of a list.
This function is equivalent to cons\*(), and should be used instead.
The last argument, l_list, must be a list. l_list can be nil, in which case a new list
containing the elements is created.The car of l_result is the first argument passed to
constar() and the cdr of l_result is rest of the elements of the newly created list
(including l_list).
Arguments
[ g_arg1 ... ] Elements to be added to the beginning of l_list.
l_list The last argument that must be a list (which can be nil).
Value Returned
l_result List whose first element is the first argument and whose cdr is
rest of the elements of the newly created list (including
l_list).
Example
The first element of the newly created list is the first argument while cdr is rest of the elements
(including l_list):
newList = constar( ’(a b) ’("hello") 1 2.3 ’(x y) )
=> ((a b) ("hello") 1 2.3 x y z)
car( newList ) => (a b)
cdr( newList ) => (("hello") 1 2.3 x y z)
SKILL Language Reference
SKILL Language Functions
August 2005 89 Product Version 06.40
The last argument can be nil:
constar( 1 2 3 nil ) => (1 2 3)
The last argument must be a list:
constar( ’x 1 2 )
*Error* constar: the last arg must be a list - 2
constar() is cleaner and more efficient in adding multiple elements to the beginning of a list
than cons():
cons(1 cons(2 cons(3 ’(a b c)))) => (1 2 3 a b c)
constar( 1 2 3 ’(a b c)) => (1 2 3 a b c)
SKILL Language Reference
SKILL Language Functions
August 2005 90 Product Version 06.40
copy
copy(
l_arg
)
=> l_result
Description
Returns a copy of a list, that is, a list with all the top-level cells duplicated.
Because list structures in SKILL are typically shared, it is usually only necessary to pass
around pointers to lists. If, however, any function that modifies a list destructively is used,
copy is often used to create new copies of a list so that the original is not inadvertently
modified by those functions. This call is costly so its use should be limited. This function only
duplicates the top-level list cells, all lower level objects are still shared.
Arguments
l_arg List of elements.
Value Returned
l_result Returns a copy of l_arg.
Example
z = '(1 (2 3) 4) => (1 (2 3) 4)
x = copy(z) => (1 (2 3) 4)
equal(z x) => t
z and x have the same value.
eq(z x) => nil
z and x are not the same list.
SKILL Language Reference
SKILL Language Functions
August 2005 91 Product Version 06.40
copy_<name>
copy_<name>(
r_defstruct
)
=> r_defstruct
Description
Creates and returns a copy of a structure. This function is created by the defstructfunction
where <name> is the name of the defstruct.
Structures can contain instances of other structures; therefore you need to be careful about
structure sharing. If sharing is not desired, use the copyDefstructDeep function to
generate a copy of the structure and its sub-elements.
Arguments
r_defstruct An instance of a defstruct.
Value Returned
r_defstruct Copy of the given instance
Example
defstruct(myStruct a b c) => t
m1 = make_myStruct(?a 3 ?b 2 ?c 1) => array[x]:xxxx
m2 = copy_myStruct(m1) => array[x]:xxxx
Reference
copyDefstructDeep, defstruct, defstructp, make_<name>, printstruct
SKILL Language Reference
SKILL Language Functions
August 2005 92 Product Version 06.40
copyDefstructDeep
copyDefstructDeep(
r_object
)
=> r_defstruct
Description
Performs a deep or recursive copy on defstructs with other defstructs as sub-elements,
making copies of all the defstructs encountered.
The various copy_<name> functions are called to create copies for the various defstructs
encountered in the deep copy.
Note: Only defstruct sub-elements are recursively copied. Other data types, like lists, are still
shared.
Arguments
r_object An instance of a defstruct.
Value Returned
r_defstruct A deep copy of the given instance.
Example
defstruct(myStruct a b c) => t ;creates a function make_myStruct
m1 = make_myStruct(?a 3 ?b 2 ?c 1)
=> array[5]:3873024
m2 = make_myStruct(?a m1 ?b '(a b c) ?c 5)
=> array[5]:3873208 ; m1 is m2's sub-element
m3 = copyDefstructDeep(m2)
=> array[5]:3873056 ; uses deep copy
m3->a
=> array[5]:3873344 ; a new object
eq(m3->a m2->a) => nil ; eq checks object identity
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SKILL Language Functions
August 2005 93 Product Version 06.40
m2->b
=> (a b c)
eq(m3->b m2->b)
=> t ; still sharing the same object because
; the sub-element b is not a defstruct
m4 = copy_myStruct(m2)
=> array[5]:3873376 ; uses shallow copy
m4->a => array[5]:3873024
eq(m4->a m2->a) => t ; share identical substructure
eq(m4->b m2->b) => t ; the same object
Reference
copy_<name>, defstruct, printstruct, defstructp
SKILL Language Reference
SKILL Language Functions
August 2005 94 Product Version 06.40
cos
cos(
n_number
)
=> f_result
Description
Returns the cosine of a floating-point number or integer.
Arguments
n_number Floating-point number or integer.
Value Returned
f_result Cosine of n_number.
Example
cos(0.3) => 0.9553365
cos(3.14/2) => 0.0007963
Reference
acos
SKILL Language Reference
SKILL Language Functions
August 2005 95 Product Version 06.40
cputime
cputime(
)
=> x_result
Description
Returns the total amount of CPU time (user plus system) used in units of 60ths of a second.
Value Returned
x_result CPU time in 60ths of a second.
Example
cputime() => 8
integerp( cputime() ) => t
floatp( cputime() ) => nil
SKILL Language Reference
SKILL Language Functions
August 2005 96 Product Version 06.40
createDir
createDir(
S_name
)
=> t | nil
Description
Creates a directory.
The directory name can be specified with either an absolute or relative path; the SKILL path
is used in the latter case. Note that a path which is anchored to current directory, for example,
./, ../, or ../../.., etc., is not considered as a relative path.
Arguments
S_name Name of the directory you are creating.
Value Returned
t If the directory is created.
nil If the directory is not created because it already exists.
If the directory cannot be created because you do not have
permission to update the parent directory, or a parent directory
does not exist, an error is signaled.
Example
createDir("/usr/tmp/test") => t
createDir("/usr/tmp/test") => nil ;Directory already exists.
Reference
deleteDir, isDir, isFile
SKILL Language Reference
SKILL Language Functions
August 2005 97 Product Version 06.40
csh
csh(
[ t_command ]
)
=> t | nil
Description
Starts the UNIX C-shell as a child process to execute a command string.
Identical to the sh function, but invokes the C-shell (csh) rather than the Bourne-shell (sh).
Arguments
t_command Command string to execute.
Value Returned
t If the exit status of executing the given shell command is 0.
nil Otherwise.
Example
csh( "mkdir ~/tmp" ) => t
Creates a sub-directory called tmp in your home directory.
Reference
sh, shell
SKILL Language Reference
SKILL Language Functions
August 2005 98 Product Version 06.40
declare
declare(
s_arrayName
[ x_sizeOfArray ]
)
=> a_newArray
Description
Creates an array with a specified number of elements. This is a syntax form. All elements of
the array are initialized to unbound.
Arguments
s_arrayName Name of the array. There must be no white space between the
name of an array and the opening bracket containing the size.
x_sizeOfArray Size of the array as an integer.
Value Returned
a_newArray Returns the new array.
Example
When the name of an array appears on the right side of an assignment statement, only a
pointer to the array is used in the assignment; the values stored in the array are not copied.
It is therefore possible for an array to be accessible by different names. Indices are used to
specify elements of an array and always start with 0; that is, the first element of an array is
element 0. SKILL checks for an out of bounds array index with each array access.
declare(a[10])
a[0] = 1
a[1] = 2.0
a[2] = a[0] + a[1]
Creates an array of 10 elements. a is the name of the array, with indices ranging from 0 to 9.
Assigns the integer 1 to element 0, the float 2.0 to element 1, and the float 3.0 to element 2.
b = a
b now also refers to the same array as a.
SKILL Language Reference
SKILL Language Functions
August 2005 99 Product Version 06.40
declare(c[10])
declares another array of 10 elements.
declare(d[2])
declares d as array of 2 elements.
d[0] = b
d[0] now refers to the array pointed to by b and a.
d[1] = c
d[1] is the array referred to by c.
d[0][2]
Accesses element 2 of the array referred to by d[0].
This is the same element as a[2].
Brackets ([]) are used in this instance to represent array references and are part of the
statement syntax.
Reference
makeVector
SKILL Language Reference
SKILL Language Functions
August 2005 100 Product Version 06.40
declareLambda
declareLambda(
s_name1 ...
s_nameN
)
=> s_nameN
Description
Tells the evaluator that certain (forward referenced) functions are of lambda type (as
opposed to nlambda or macro).
Declares s_name1 ... s_nameN as procedures (lambdas) to be defined later. This is
much like C’s “extern” declarations. Because the calling sequence for nlambdas is quite
different from that of lambdas, the evaluator needs to know the function type in order to
generate more efficient code. Without the declarations, the evaluator can still handle things
properly, but with some performance penalty. The result of evaluating this form is the last
name given (in addition to the side-effects to the evaluator).
This (and declareNLambda) form has effect only on undefined function names, otherwise it
is ignored. Also, when the definition is provided later, if it is of a different function type (for
example, declared as lambda but defined as nlambda) a warning will be given and the
definition is used regardless of the declaration. In this case (definition is inconsistent with
declaration), if there is any code already loaded that made forward references to these
names, that part of code should be reloaded in order to use the correct calling sequence.
Arguments
s_name1 One or more function names.
Value Returned
s_nameN The last name in the arguments.
Example
declareLambda(fun1 fun2 fun3) => fun3
SKILL Language Reference
SKILL Language Functions
August 2005 102 Product Version 06.40
declareNLambda
declareNLambda(
s_name1 ...
s_nameN
)
=> s_nameN
Description
Tells the evaluator that certain (forward referenced) functions are of nlambda type (as
opposed to lambdas or macros).
Declares s_name1 ... s_nameN as nprocedures (nlambdas) to be defined later. This
is much like C’s “extern” declarations. Because the calling sequence for nlambdas is quite
different from that of lambdas, the evaluator needs to know the function type in order to
generate more efficient code. Without the declarations, the evaluator can still handle things
properly, but with some performance penalty. The result of evaluating this form is the last
name given (in addition to the side-effects to the evaluator).
Arguments
s_name1 One or more function names.
Value Returned
s_nameN The last name in the arguments.
Example
declareNLambda(nfun1 nfun2 nfun3) => nfun3
Reference
declareLambda
SKILL Language Reference
SKILL Language Functions
August 2005 103 Product Version 06.40
declareSQNLambda
declareSQNLambda(
s_functionName ...
)
=> nil
Description
Declares the given nlambda functions to be solely-quoting nlambdas.
This is an nlambda function. The named functions are defined as nlambdas only to save
typing the explicit quotes to the arguments.
The compiler has been instructed to allow the calling of these kinds of nlambdas from
SKILL++ code without giving a warning message.
All the debugging commands have been declared as SQNLambdas already.
Arguments
s_functionName Function to be declared as a solely-quoting nlambda.
Value Returned
nil Always. This function is for side-effects only.
Example
declareSQNLambda( step next stepout ) => nil
SKILL Language Reference
SKILL Language Functions
August 2005 104 Product Version 06.40
define - SKILL++ mode
define(
s_var
g_expression
)
=> s_var
define(
(
s_var
[ s_formalVar1 ... ]
)
g_body ...
)
=> s_var
Description
define, used in SKILL++ mode only, is a syntax form used to provide a definition for a
global or local variable. The define syntax form has two variations.
Definitions are allowed only at the top-level of a program and at the beginning of a body within
the following syntax forms: lambda, let, letrec, and letseq. If occurring within a body,
the define's variable is local to the body.
■ Top Level Definitions
A definition occurring at the top level is equivalent to an assignment statement to a global
variable.
■ Internal Definitions
A definition that occurs within the body of a syntax form establishes a local variable
whose scope is the body.
■ define( s_var g_expression )
This is the primary variation. The other variation can be rewritten in this form. The
expression is evaluated in enclosing lexical environment and the result is assigned or
bound to the variable.
■ define( ( s_var [s_formalVar1 ...] ) g_body )
In this variation, body is a sequence of one or more expressions optionally preceded by
one or more nested definitions. This form is equivalent to the following define
define( s_var
lambda(( [sformalVar1 ...] ) g_body ...)
SKILL Language Reference
SKILL Language Functions
August 2005 105 Product Version 06.40
Example
■ First variation
define( x 3 ) => x
define( addTwoNumbers lambda( ( x y ) x+y ) )
=> addTwoNumbers
■ Second variation
define( ( addTwoNumbers x y ) x+y )
=> addTwoNumbers
■
Local definition using second variation
let( (( x 3 ))
define( ( add y ) x+y ) ; define
add( 5 )
) ; let
=> 8
Defines a local function add, then invokes it.
let( ()
define( ( f n )
if( n > 0 then n*f(n-1) else 1 ) ; if
) ; define
f( 5 )
) ; let
=> 120
Declares a single recursive local function f that computes the factorial of its argument.
The let expression returns the factorial of 5.
Reference
lambda, let - SKILL mode, letrec - SKILL++ mode,letseq - SKILL++ mode, begin -
SKILL++ mode
SKILL Language Reference
SKILL Language Functions
August 2005 106 Product Version 06.40
defmacro
defmacro(
s_macroName
( l_formalArglist )
g_expr1 ...
)
=> s_macroName
Description
Defines a macro which can take a list of formal arguments including @optional, @key, and
@rest (instead of the more restrictive format as required by using mprocedure).
The actual arguments will be matched against the formals before evaluating the body.
Arguments
s_macroName Name of the macro you are defining.
l_formalArglist Formal argument list.
g_expr1 Expression or expressions to be evaluated.
Value Returned
s_macroName Returns the name of the macro being defined.
Example
defmacro( whenNot (cond @rest body)
‘(if ! ,cond then ,@body) )
=> whenNot
expandMacro( '(whenNot x > y z = f(y) x*z) )
=> if(!(x > y) then (z = (f y))(x * z))
whenNot(1 > 2 "hello" 1+2)
=> 3
Reference
expandMacro, isMacro, mprocedure
1
2
---
SKILL Language Reference
SKILL Language Functions
August 2005 107 Product Version 06.40
defMathConstants
defMathConstants(
s_id
)
=> s_id
Description
Associates a set of predefined math constants as properties of the given symbol.
Arguments
s_id Must be a symbol. The properties to be associated with the
symbol are listed as name/value pairs. The names are explained
in the following table.
Name Meaning
E The base of natural logarithms. (e)
LOG2E The base-2 logarithm of e
LOG10E The base-10 logarithm of e
LN2 The natural logarithm of 2.
LN10 The natural logarithm of 10.
PI The ratio of the circumference of a circle to its
diameter. ( π )
PI_OVER_2 π /2
PI_OVER_4 π /4
ONE_OVER_PI 1/π
TWO_OVER_PI 2/π
TWO_OVER_SQRTPI
SQRT_TWO (The positive square root of 2.)
SQRT_POINT_FIVE (The positive square root of 1/2.)
INT_MAX The maximum value of a SKILL integer.
INT_MIN The minimum value of a SKILL integer.
2 π()⁄
2
SKILL Language Reference
SKILL Language Functions
August 2005 108 Product Version 06.40
Value Returned
s_id Returns the symbol ID.
Example
defMathConstants(‘m) => m
m.?? => (
SQRT_POINT_FIVE 0.7071068
SQRT_TWO 1.414214
TWO_OVER_SQRTPI 1.128379
TWO_OVER_PI 0.6366198
ONE_OVER_PI 0.3183099
PI_OVER_4 0.7853982
PI_OVER_2 1.570796
PI 3.141593
LN10 2.302585
LN2 0.6931472
LOG10E 0.4342945
LOG2E 1.442695
E 2.718282
DBL_MIN 2.225074e-308
DBL_MAX 1.797693e+308
INT_MIN -2147483648
INT_MAX 2147483647
SHRT_MIN -32768
SHRT_MAX 32767)
m.SQRT_POINT_FIVE => 0.7071068
m.INT_MIN => -2147483648
m.PI => 3.141593
printf(“%0.17f\n” m.PI) => 3.14159265358979312
Reference
printf, getqq, plist, setplist
DBL_MAX The maximum value of a SKILL double.
DBL_MIN The minimum value of a SKILL double.
SHRT_MAX The maximum value of a SKILL "short" integer.
SHRT_MIN The minimum value of a SKILL "short" integer.
Name Meaning
SKILL Language Reference
SKILL Language Functions
August 2005 109 Product Version 06.40
defprop
defprop(
s_id
g_value
s_name
)
=> g_value
Description
Adds properties to symbols but none of its arguments are evaluated. This is a syntax form.
The same as putprop except that none of its arguments are evaluated.
Arguments
s_id Symbol to add property to.
g_value Value of the named property.
s_name Named property.
Value Returned
g_value Value of the named property.
Example
defprop(s 3 x) => 3
Sets property x on symbol s to 3.
defprop(s 1+2 x) => (1+2)
Sets property x on symbol s to the unevaluated expression 1+2.
Reference
get, putprop
SKILL Language Reference
SKILL Language Functions
August 2005 110 Product Version 06.40
defstruct
defstruct(
s_name
s_slot1
[ s_slot2.. ]
)
=> t
Description
Creates a defstruct, a named structure that is a collection of one or more variables.
Defstructs can have slots of different types that are grouped together under a single name
for handling purposes. They are the equivalent of structs in C. The defstruct form also
creates an instantiation function, named make_<name> where <name> is the structure
name supplied to defstruct. This constructor function takes keyword arguments: one for
each slot in the structure. Once created, structures behave just like disembodied property
lists.
Note: Just like disembodied property lists, structures can have new slots added at any time.
However these dynamic slots are less efficient than the statically declared slots, both in
access time and space utilization.
Structures can contain instances of other structures; therefore one needs to be careful about
structure sharing. If sharing is not desired, a special copy function can be used to generate a
copy of the structure being inserted. The defstruct form also creates a function for the
given defstruct called copy_<name>. This function takes one argument, an instance of
the defstruct. It creates and returns a copy of the given instance. An example appears
after the description of the other defstruct functions.
Arguments
s_name A structure name.
s_slot1 Name of the first slot in structure s_name.
s_slot2 Name of the second slot in structure s_name.
Value Returned
t Always.
SKILL Language Reference
SKILL Language Functions
August 2005 111 Product Version 06.40
Example
defstruct(myStruct slot1 slot2 slot3) => t
struct = make_myStruct(?slot1 "one" ?slot2 "two"
?slot3 "three")
struct->slot1 => "one"
Returns the value associated with a slot of an instance.
struct->slot1 = "new" => "new"
Modifies the value associated with a slot of an instance.
struct->? => (slot3 slot2 slot1)
Returns a list of the slot names associated with an instance.
struct->?? => (slot3 "three" slot2 "two" slot1 "new")
Returns a property list (not a disembodied property list) containing the slot names and values
associated with an instance.
Reference
defstructp, printstruct
SKILL Language Reference
SKILL Language Functions
August 2005 112 Product Version 06.40
defstructp
defstructp(
g_object
[ S_name ]
)
=> t | nil
Description
Checks if an object is an instance of a particular defstruct.
If the optional second argument is given, it is used as the defstruct name to check against.
The suffix pis usually added to the name of a function to indicate that it is a predicate function.
Arguments
g_object A data object.
S_name Name of the structure to be tested for.
Value Returned
t If g_object is an instance of defstruct S_name.
nil Otherwise.
Example
defstruct(myStruct slot1 slot2 slot3)
=> t
struct = make_myStruct(?slot1 "one" ?slot2 "two" ?slot3 "three")
=> array[5]:3555552
defstructp( "myDefstruct")
=> nil
defstructp(struct 'myStruct)
=> t
Reference
defstruct, printstruct
SKILL Language Reference
SKILL Language Functions
August 2005 113 Product Version 06.40
defun
defun(
s_funcName
( l_formalArglist )
g_expr1 ...
)
=> s_funcName
Description
Defines a function with the name and formal argument list you specify. This is a syntax form.
The body of the procedure is a list of expressions to be evaluated one after another when
s_funcName is called. There must be no white space between defun and the open
parenthesis that follows.
However, for defun there must be white space between s_funcName and the open
parenthesis. This is the only difference between the defun and procedure forms. defun
has been provided principally so that you can make your code appear more like other LISP
dialects.
Expressions within a function can reference any variable on the formal argument list or any
global variable defined outside the function. If necessary, local variables can be declared
using the let function.
Arguments
s_funcName Name of the function you are defining.
l_formalArglist Formal argument list.
g_expr1 Expression or expressions to be evaluated when s_funcName
is called.
Value Returned
s_funcName The name of the function being defined.
SKILL Language Reference
SKILL Language Functions
August 2005 114 Product Version 06.40
ARGUMENT LIST PARAMETERS
Several parameters provide flexibility in procedure argument lists. These parameters are
referred to as @ (“at” sign) options. The parameters are @rest, @optional, and @key. See
procedure for a detailed description of these argument list parameters.
Example
procedure( cube(x) x**3 ) ; Defines a function to compute the
=> cube ; cube of a number using procedure.
cube( 3 ) => 27
defun( cube (x) x**3 ) ; Defines a function to compute the
=> cube ; cube of a number using defun.
The following function computes the factorial of its positive integer argument by recursively
calling itself.
procedure( factorial(x)
if( (x == 0) then 1
else x * factorial(x - 1))) => factorial
defun( factorial (x)
if( (x == 0) then 1
else x * factorial( x - 1))) => factorial
factorial( 6 )=> 720
Reference
procedure, let - SKILL mode, prog, nprocedure - SKILL mode only, nlambda - SKILL
mode only
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defUserInitProc
defUserInitProc(
t_contextName
s_procName
)
=> ( t_contextName s_procName )
Description
Registers a user-defined function that the system calls immediately after autoloading a
context.
Lets you customize existing Cadence contexts. In the general case, most Cadence-supplied
contexts have internally defined an initialization function through the defInitProc function.
This function defines a second initialization function, called after the internal initialization
function, thereby allowing you to customize on top of Cadence supplied contexts. This is best
done in the .cdsinit file.
Arguments
t_contextName Name of context file to load.
s_procName Function to be called when context file is loaded.
Value Returned
((t_contextName s_procName))
Always returns an association list when set up. Note that the
function is not actually called at this point, but is called when the
t_contextName context is loaded.
Example
defUserInitProc( "myContext" 'initMyContext)
=> (("myContext" initMyContext))
Reference
defInitProc, callInitProc
SKILL Language Reference
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defvar - SKILL mode only
defvar(
s_varName
[ g_value ]
)
=> g_value | nil
Description
Defines a global variable and assigns it a value. Use in SKILL mode only. Use the define
syntax form to define global variables in SKILL++ mode.
Arguments
s_varName Name of the variable to be defined.
g_value Value to assign to the variable. If g_value is not given, nil is
assigned to the variable.
Value Returned
g_value If given.
nil Otherwise.
Example
defvar(x 3) => 3
Assigns x a value of 3.
Reference
defprop, set, setq
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deleteDir
deleteDir(
S_name
)
=> t | nil
Description
Deletes a directory.
The directory name can be specified with either an absolute or relative path; the SKILL path
is used in the latter case. Note that a path which is anchored to current directory, for example,
./, ../, or ../../.., etc., is not considered as a relative path.
Arguments
S_name Name of directory to delete.
Value Returned
t If the directory has been successfully deleted.
nil If the directory does not exist.
Signals an error if you do not have permission to delete a
directory or the directory you want to delete is not empty.
Example
createDir("/usr/tmp/test") => t
deleteDir("/usr/tmp/test") => t
deleteDir("/usr/bin")
Signals an error about permission violation.
deleteDir("~")
Assuming there are some files in ~, signals an error that the directory is not empty.
Reference
createDir, deleteFile, isDir, isFile
SKILL Language Reference
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August 2005 118 Product Version 06.40
deleteFile
deleteFile(
S_name
)
=> t | nil
Description
Deletes a file.
The file name can be specified with either an absolute or relative path; the SKILL path is used
in the latter case. If a symbolic link is passed in as the argument, it is the link itself, not the file
or directory referenced by the link, that gets removed. Note that a path which is anchored to
current directory, for example, ./, ../, or ../../.., etc., is not considered as a relative
path.
Arguments
S_name Name of file you want to delete.
Value Returned
t File is successfully deleted.
nil File does not exist.
Signals an error if you do not have permission to delete a file.
Example
deleteFile("~/test/out.1") => t
If the named file exists and is deleted.
deleteFile("~/test/out.2") => nil
If the named file does not exist.
deleteFile("/bin/ls")
If you do not have write permission for /bin, signals an error about permission violation.
SKILL Language Reference
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August 2005 120 Product Version 06.40
difference
difference(
n_op1
n_op2
[ n_op3 ... ]
)
=> n_result
Description
Returns the result of subtracting one or more operands from the first operand. Prefix form of
the - arithmetic operator.
Arguments
n_op1 Number from which the others are to be subtracted.
n_op2 Number to subtract.
n_op3 Optional additional numbers to subtract.
Value Returned
n_result Result of the operation.
Example
difference(5 4 3 2 1) => -5
difference(-12 13) => -25
difference(12.2 -13) => 25.2
Reference
xdifference
SKILL Language Reference
SKILL Language Functions
August 2005 121 Product Version 06.40
display
display(
g_obj
[ p_port ]
)
=> t | nil
Description
Writes a representation of an object to the given port.
Strings that appear in the written representation are not enclosed in double quotes, and no
characters are escaped within those strings.
Arguments
g_obj Any SKILL object.
p_port Optional output port. poport is the default.
Value Returned
t Usually ignored. Function is for side effects only.
nil Usually ignored. Function is for side effects only.
Example
(display "Hello!")
=> t
The side effect is to display Hello! to poport.
Reference
drain, print, write
SKILL Language Reference
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August 2005 122 Product Version 06.40
do - SKILL++ mode only
do(
(
(
s_var1
g_initExp1
[ g_stepExp1 ]
)
(
s_var2
g_initExp2
[ g_stepExp2 ]
) ...
)
(
g_terminationExp
g_terminationExp1 ...
)
g_loopExp1
g_loopExp2 ...
)
=> g_value
Description
Iteratively executes one or more expressions. Used in SKILL++ mode only.
Use do to iteratively execute one or more expressions. The do expression provides a do-
while facility allowing multiple loop variables with arbitrary variable initializations and step
expressions. You can declare
■ One or more loop variables, specifying for each variable both its initial value and how it
gets updated each time around the loop.
■ A termination condition which is evaluated before the body expressions are executed.
■ One or more termination expressions to be evaluated upon termination to determine a
return value.
A do Expression Evaluates in Two Phases
■ Initialization phase
The initialization expressions g_initExp1, g_initExp2, ... are evaluated in an
unspecified order and the results bound to the local variables var1, var2, ...
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■ Iteration phase
This phase is a sequence of steps, informally described as going around the loop zero
or more times with the exit determined by the termination condition.
More formally stated:
1. Each iteration begins by evaluating the termination condition.
If the termination condition evaluates to a non-nil value, the do expression exits with a
return value computed as follows:
2. The termination expressions terminationExp1, terminationExp2, ... are
evaluated in order. The value of the last termination condition is returned as the value of
the do expression.
Otherwise, the do expression continues with the next iteration as follows.
3. The loop body expressions g_loopExp1, g_loopExp2, ... are evaluated in order.
4. The step expressions g_stepExp1, g_stepExp2, ..., if given, are evaluated in an
unspecified order.
5. The local variables var1, var2, ... are bound to the above results. Reiterate from step
one.
Example
By definition, the sum of the integers 1, ..., N is the Nth triangular number. The following
example finds the first triangular number greater than a given limit.
procedure( trTriangularNumber( limit )
do(
( ;;; start loop variables
( i 0 i+1 )
( sum 0 ) ;;; no step expression
;;; same as ( sum 0 sum )
) ;;; end loop variables
( sum > limit ;;; test
sum ;;; return result
)
sum = sum+i ;;; body
) ; do
) ; procedure
trTriangularNumber( 4 ) => 6
trTriangularNumber( 5 ) => 6
trTriangularNumber( 6 ) => 10
SKILL Language Reference
SKILL Language Functions
August 2005 125 Product Version 06.40
drain
drain(
[ p_outputPort ]
)
=> t | nil
Description
Writes out all characters that are in the output buffer of a port.
Analogous to fflush in C (plus fsync if the port is a file). Not all systems guarantee that
the disk is updated on each write. As a result, it is possible for a set of seemingly successful
writes to actually fail when the port is closed.
To protect your data, call drain after a logical set of writes to a file port. It is not
recommended that you call drain after every write however, because this could impact your
program's performance.
Arguments
p_outputPort Port to flush output from. If no argument is given this function
does nothing.
Value Returned
t If all buffered data was successfully written out.
nil There was a problem writing out the data, and some or all of it
was not successfully written out.
Signals an error if the port to be drained is an input port or has
been closed.
Example
drain() => t
drain(poport) => t
myPort = outfile("/tmp/myfile")
=> port:"/tmp/myfile"
for(i 0 15 fprintf(myPort "Test output%d\n" i))
=> t
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system( "ls -l /tmp/myfile")
--rw-r--r-- 1 root 0 Aug12 14:44 /tmp/myFile
fileLength( "/tmp/myfile")
=> 0
drain(myPort)
=> t
fileLength( "/tmp/myfile" )
=> 230
close(myPort)
=> t
drain(myPort)
=> *Error* drain: cannot send output to a closed port - port:
"/tmp/myfile"
drain(piport)
=> *Error* drain: cannot send output to an input port -
port:"*stdin*"
drain(poport)
=> t
defun(handleWriteError (x)
printf("WARNING - %L write unsuccessful\n" x) nil)
=> handleWriteError
myPort=outfile("/tmp/myfile")
=> port:"/tmp/myfile"
for(i 0 15 fprintf(myPort "%d\n" (2**i)))
=> t
if(!drain(myPort) handleWriteError(myPort) t)
=> t
Reference
outfile, close
SKILL Language Reference
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August 2005 127 Product Version 06.40
dtpr
dtpr(
g_value
)
=> t | nil
Description
Checks if an object is a non-empty list.
dtpr is a predicate function that is equivalent to pairp.
Arguments
g_value An object.
Value Returned
t Object is a non-empty list.
nil Otherwise. Note that dtpr(nil) returns nil.
Example
dtpr( 1 ) => nil
dtpr( list(1)) => t
Reference
listp, null, pairp
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August 2005 128 Product Version 06.40
ed
ed(
[ t_fileName ]
)
=> t | nil
Description
Edits the named file.
Arguments
t_fileName File to edit. If no argument is given, defaults to the previously
edited file, or temp.il, if there is no previous file.
Value Returned
t The operation was successfully completed.
nil The file does not exist or there is an error condition.
Reference
edi, edl, edit
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edi
edi(
[ t_fileName ]
)
=> t | nil
Description
Edits the named file, then includes the file into SKILL.
Arguments
t_fileName File to edit. If no argument is given, defaults to the previously
edited file, or temp.il, if there is no previous file.
Value Returned
t The operation was successfully completed.
nil The file does not exist or there is an error condition.
Example
edi( "~/myFile.il" )
Reference
ed, edit, edl
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August 2005 130 Product Version 06.40
edit
edit(
S_object
[ g_loadFlag ]
)
=> x_childId
Description
Edits a file, function, or variable. This function only works if you are in graphical mode. This
is an nlambda function.
edit brings up an editor window in a separate process and thus doesn’t lock up the CIW. If
the object being edited is a function that was loaded after debug mode was turned on, then
edit opens up the file that contains the function. If the editor is vi or emacs it jumps to the
start of the function. If g_loadFlag is t the file is loaded into SKILL when the editor is
exited. Be sure the editor variable is set up properly if you are using an editor other than
vi or emacs.
Arguments
S_object If you are editing a file, the object you are editing must be a
string. If you are editing a function or variable, it must be an
unquoted symbol.
g_loadFlag Determines whether to load the file after the editor window is
exited.
Valid values: t or nil
Default: nil.
Value Returned
x_childId Integer identifying the process spawned for the editor.
Example
edit( "~/.cdsinit" )
Edits the .cdsinit file in your home directory.
edit( myFun)
SKILL Language Reference
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edl
edl(
[ t_fileName ]
)
=> t | nil
Description
Edits the named file, then loads the file into SKILL.
Arguments
t_fileName File to edit. If no argument is given, defaults to the previously
edited file, or temp.il, if there is no previous file.
Value Returned
t The operation was successfully completed.
nil The file does not exist or there is an error condition.
Example
edl( "/tmp/demo.il" )
Reference
ed, edi, edit
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envobj
envobj(
x_id
)
=> e_environment
Description
Returns the environment object whose print representation has the ID x_id. You can
consider x_id to be the address of the environment object.
Arguments
x_id The environment object’s ID.
Value Returned
e_environment Environment object specified by the given object ID. An error is
signaled if the given object ID does not designate an
environment object.
Example
E = theEnvironment() => envobj:0x1ad018
;only meaningful in SKILL++ mode
eq( envobj( 0x1ad018 ) E ) => t
This example retrieves the enclosing lexical environment and assigns it to a variable. Next
extract the ID by inspection from the print representation, and pass it to the envobj function.
Using the eq function demonstrates that return value is E.
Reference
funobj, theEnvironment - SKILL++ mode only
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eq
eq(
g_arg1
g_arg2
)
=> t | nil
Description
Checks addresses when testing for equality.
Returns t if g_arg1 and g_arg2 are exactly the same (that is, are at the same address in
memory). The eq function runs considerably faster than equal but should only be used for
testing equality of symbols or shared lists. Using eqon types other than symbols and lists will
give unpredictable results and should be avoided.
For testing equality of numbers, strings, and lists in general, the equal function and not the
eq function should be used. You can test for equality between symbols using eq more
efficiently than using the == operator, which is the same as the equal function.
Arguments
g_arg1 Any SKILL object. g_arg1 is compared with g_arg2 to see if
they point to the same object.
g_arg2 Any SKILL object.
Value Returned
t Both arguments are the same object.
nil The two objects are not identical.
Example
x = 'dog
eq( x 'dog ) => t
eq( x 'cat ) => nil
y = 'dog
eq( x y ) => t
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equal
equal(
g_arg1
g_arg2
)
=> t | nil
Description
Checks contents of strings and lists when testing for equality.
Checks if two arguments are equal or if they are logically equivalent, for example, g_arg1
and g_arg2 are equal if they are both lists/strings and their contents are the same. Note that
this test is slower than using eq but works for comparing objects other than symbols.
■ If the arguments are the same object in virtual memory (that is, they are eq), equal
returns t.
■ If the arguments are the same type and their contents are equal (for example, strings with
identical character sequence), equal returns t.
■ If the arguments are a mixture of fixnums and flonums, equal returns t if the numbers
are identical (for example, 1.0 and 1).
Arguments
g_arg1 Any SKILL object. g_arg1 and g_arg2 are tested to see if they
are logically equivalent.
g_arg2 Any SKILL object.
Value Returned
t If g_arg1 and g_arg2 are equal.
nil Otherwise.
Example
x = 'cat
equal( x 'cat ) => t
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eqv
eqv(
g_obj1
g_obj2
)
=> t | nil
Description
Tests for object identity or equality between two numbers of the same type (for example, both
numbers are integers). Except for numbers, eqv is like eq.
Arguments
g_obj1 Any SKILL object.
g_obj2 Any SKILL object.
Value Returned
t g_obj1 and g_obj2 are the same object or the same number.
nil Otherwise.
Example
(eqv 1.5 1.5) => t
(equal 1.5 1.5) => t
(eq 1.5 1.5) => nil
(eqv (list 1 2) (list 1 2)) => nil
Reference
eq, equal
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August 2005 139 Product Version 06.40
err
err(
[ g_value ]
)
=> none
Description
Causes an error.
If this error is caught by an errset, nil is returned by that errset. However, if the optional
g_value argument is given then g_value is returned from the errset and can be used
to identify which err signaled the error. The err function never returns a value.
Arguments
g_value SKILL object that becomes the return value for errset.
Value Returned
Never returns a value.
Example
errset( err( 'ErrorType)) => (ErrorType)
errset.errset => nil
procedure( test( x )
if( (equal errset( foo( x )) '(throw))
then println( "Throw caught" )
else if( errset.errset println( "Error: divide by
zero"))))=> test
procedure( foo( x )
if( (equal (4 / x) 1)
then err( 'throw )
else println( x )))=> foo
test( 4 ) => nil ; Prints Throw caught
test( 2 ) => nil ; Prints 2
test( 0 ) => nil ; Prints Error: divide by zero
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error
error(
[ S_message1
[ S_message2 ] ... ]
)
=> none
Description
Prints error messages and calls err.
Prints the S_message1 and S_message2 error messages if they are given and then calls
err, causing an error. The first argument can be a format string, which causes the rest of the
arguments to be printed in that format.
Arguments
S_message1 Message string or symbol.
S_message2 More message strings or symbols. Note that more than two
arguments should be given only if the first argument is a format
string.
Value Returned
Prints the S_message1 and S_message2 error messages if they are given and then calls
err, causing an error. error never returns.
Example
error( "myFunc" "Bad List")
Prints *Error* myFunc: Bad List
error( "bad args - %s %d %L" "name" 100 '(1 2 3) )
Prints *Error* bad args - name 100 (1 2 3)
errset( error( "test" ) t) => nil
Prints out *Error* test and returns nil.
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errset
errset(
g_expr
[ g_errprint ]
)
=> l_result | nil
Description
Encapsulates the execution of an expression in an environment safe from the error
mechanism. This is a syntax form.
If an error occurs in the evaluation of the given expression, control always returns to the
command following the errset instead of returning to the nearest toplevel. If g_errprint
is non-nil, error messages are issued; otherwise they are suppressed. In either case,
information about the error is placed in the errset property of the errset symbol.
Programs can therefore access this information with the errset.errset construct after
determining that errset returned nil.
Arguments
g_expr Expression to be evaluated; while evaluating it, any errors cause
immediate return from the errset.
g_errprint Flag to control the printout of error messages. If tthen prints the
error message encountered in errset, defaults to nil.
Value Returned
l_result List with value from successful evaluation of g_expr.
nil An error occurred.
Example
errset(1+2) => (3)
errset.errset => nil
errset(sqrt('x)) => nil
Because sqrt requires a numerical argument.
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errsetstring
errsetstring(
t_string
[ g_errprint ]
[ s_langMode ]
)
=> l_value | nil
Description
Reads and evaluates an expression stored in a string. Same as evalstring except that it
calls errset to catch any errors that might occur during the parsing and evaluation.
If an error has occurred, nil is returned, otherwise a list containing the value of the
evaluation is returned. Should an error occur, it is stored in errset.errset. If errprint
is non-nil, error messages are printed out; otherwise they are suppressed.
Arguments
t_string String to be evaluated.
g_errprint Flag for controlling the printout of error messages. If t, then
prints the error message encountered in errset. Defaults to
nil.
s_langMode Must be a symbol.
Valid values:
Value Returned
l_value List with the value from successful evaluation of t_string.
nil An error occurs.
'ils Evaluates the given string in SKILL++ mode.
'il Evaluates the given string in SKILL mode. This is the
default.
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Example
errsetstring("1+2") => (3)
errsetstring("1+'a") => nil
Returns nil because an error occurred.
errsetstring("1+'a" t) => nil
Prints out error message:
*Error* plus: can't handle (1+a)...
Reference
err, error, errset, evalstring
SKILL Language Reference
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August 2005 147 Product Version 06.40
eval
eval(
g_expression
[ e_environment ]
)
=> g_result
Description
Evaluates an argument and returns its value. If an environment argument is given,
g_expression is treated as SKILL++ code, and the expression is evaluated in the given
(lexical) environment. Otherwise g_expression is treated as SKILL code.
This function gives you control over evaluation. If the optional second argument is not
supplied, it takes g_expression as SKILL code. If an environment argument is given, it
treats g_expression as SKILL++ code, and evaluates it in the given (lexical) environment.
For SKILL++'s eval, if the given environment is not the top-level one, the effect is like
evaluating g_expression within a let construct for the bindings in the given environment,
with the following exception:
If g_expression is a definitional form (such as (define ...)), it is treated as a global
definition instead of local one. Therefore any variables defined will still exist after executing
the eval form.
Arguments
g_expression Any SKILL expression.
e_environment If this argument is given, SKILL++ semantics is assumed. The
forms entered will be evaluated within the given (lexical)
environment.
Value Returned
g_result Result of evaluating g_expression.
Example
eval( 'plus( 2 3 ) ) => 5
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evalstring
evalstring(
t_string
[ s_langMode ]
)
=> g_value | nil
Description
Reads and evaluates an expression stored in a string.
The resulting value is returned. Notice that evalstring does not allow the outermost set of
parentheses to be omitted from the evaluated expression, as in load or in the top level.
Arguments
t_string String containing the SKILL expression to be evaluated.
s_langMode Must be a symbol.
Valid values:
Value Returned
g_value The value of the argument expression after evaluation.
nil No form is read.
Example
evalstring("1+2") => 3
The 1+2 infix notation is the same as (plus 1 2).
evalstring("cons('a '(b c))") => (a b c)
car '(1 2 3) => 1
evalstring("car '(1 2 3)")
Signals that car is an unbound variable.
'ils Evaluates the given string in SKILL++ mode.
'il Evaluates the given string in SKILL mode. This is
the default.
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evenp
evenp(
x_num
)
=> t | nil
Description
Checks if a number is an even integer.
Arguments
x_num Number to check.
Value Returned
t If x_num is an even integer.
nil Otherwise.
Example
evenp( 59 )
=> nil
evenp( 60 )
=> t
evenp( 2.0 )
=> nil ; Number is even, but not an integer.
Reference
minusp, oddp, onep, plusp, zerop
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exists
exists(
s_formalVar
l_valueList
g_predicateExpr
)
=> g_result
exists(
s_key
o_table
g_predicateExpr
)
=> t | nil
Description
Returns the first tail of l_valueList whose car satisfies a predicate expression. Also
verifies whether an entry in an association table satisfies a predicate expression. This is a
syntax form.
This process continues to apply the cdr function successively through l_valueList until
it finds a list element that causes g_predicateExpr to evaluate to non-nil. It then
returns the tail that contains that list element as its first element.
This function can also be used to verify whether an entry in an association table satisfies
g_predicateExpr.
Arguments
s_formalVar Local variable that is usually referenced in
g_predicateExpr.
l_valueList List of elements that are bound to s_formalVar, one at a time.
g_predicateExpr SKILL expression that usually uses the value of s_formalVar.
s_key Key portion of an association table entry.
o_table Association table containing the entries to be processed.
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Value Returned
g_result First tail of l_valueList whose car satisfies
g_predicateExpr.
nil If none of the elements in l_valueList can satisfy it.
t Entry in an association table satisfies g_predicateExpr.
Example
exists( x '(1 2 3 4) (x > 1) ) => (2 3 4)
exists( x '(1 2 3 4) (x > 4) ) => nil
exists( key myTable (and (stringp key)
(stringp myTable[key])))
=> t
Tests an association table and verifies the existence of an entry where both the key and its
corresponding value are of type string.
Reference
car, cdr, forall
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August 2005 154 Product Version 06.40
exit
exit(
[ x_status ]
)
=> nil
Description
Causes SKILL to exit with a given process status (defaults to 0), whether in interactive or
batch mode.
Use exit functions to customize the behavior of an exit call. Sometimes you might like to do
certain cleanup actions before exiting SKILL. You can do this by registering exit-before and/
or exit-after functions.
An exit-before function is called before exit does anything, and an exit-after function is
called after exit has performed its bookkeeping tasks and just before it returns control to the
operating system. The user-defined exit functions do not take any arguments.
To give you even more control, an exit-before function can return the atom ignoreExit to
abort the exit call totally. When exit is called, first all the registered exit-before functions
are called in the reverse order of registration. If any of them returns the special atom
ignoreExit, the exit request is aborted and it returns nil to the caller.
After the exit-before functions are called:
1. Some bookkeeping tasks are called.
2. All the registered exit-after functions are called in the reverse order of their registration.
3. Finally the process exits to the operating system.
For compatibility with earlier versions of SKILL, you can still define the functions named
exitbefore and exitafter as one of the exit functions. They are treated as the first
registered exit functions (the last to be called). To avoid confusing the system setup, do not
use these names for other purposes.
Arguments
x_status Process exit status; defaults to 0.
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Value Returned
nil The exit request is aborted. Otherwise there is no return value
because the process exits.
Example
(defun myExitBefore ()
(if (closeMyDataBase)
t ; if OK in closeMyDataBase then exit
'ignoreExit)) ; otherwise we want to abort exit
regExitBefore('myExitBefore)
=> t ; exit function is registered
exit()
Depending on the result from calling closeMyDataBase, the system either exits the
application (after asking for confirmation if running in graphic mode) or aborts the exit and
returns nil.
Reference
regExitBefore, regExitAfter
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exp
exp(
n_number
)
=> f_result
Description
Raises e to a given power.
Arguments
n_number Power to raise e to.
Value Returned
f_result Value of e raised to the n_numberth power.
Example
exp( 1 ) => 2.718282
exp( 3.0) => 20.08554
Reference
acos, asin, atan, cos, log, sin, tan
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expandMacro
expandMacro(
g_form
)
=> g_expandedForm
Description
Expands one level of macro call for a form.
Checks if the given form g_form is a macro call and returns the expanded form if it is.
Otherwise it returns the original argument. The macro expansion is done only once (one
level). That is, if the expanded form is another macro call, it is not further expanded (unless
another expandMacro is called with the expanded form as its argument).
Arguments
g_form Form that can be a macro call.
Value Returned
g_expandedForm Expanded form or the original form if the given argument is not a
macro call.
Example
mprocedure( testMsg(args)
‘(printf "test %s -- %L\n" ,(cadr args)progn(,@(cddr args))) )
=> testMsg
expandMacro( '(testMsg "alpha1" y = f(x) g(y 100)) )
=> printf("test %s -- %L\n" "alpha1"
progn((y = (f x)) (g y 100)))
Reference
mprocedure, defmacro
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expt
expt(
n_base
n_power
)
=> n_result
Description
Returns the result of raising a base number to a power. Prefix form of the ** exponentiation
operator.
Arguments
n_base Number to be raised to a power.
n_power Power to which the number is raised.
Value Returned
n_result Result of the operation.
Example
expt(2 3) => 8
expt(-2 3) => -8
expt(3.3 2) => 10.89
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fboundp
fboundp(
s_functionName
)
=> t | nil
Description
Returns true (that is, some non-nil value) if the given name has a function binding.
This function returns a non-nil (that is, true) value if the given name has a function binding
and returns nil otherwise. Note that fboundp examines the current function binding only
and does not check for any potential definitions from autoloading. fboundp can be
considered as an alias to getd.
Arguments
s_functionName Name to check for function binding.
Value Returned
t If there is a function binding for the given name.
nil If no function binding exists currently for the name.
Example
fboundp( 'xyz ) => nil ;assuming there is no function named xyz
fboundp( 'defstruct) => funobj:0x261108 ;a non-nil result
Reference
getd
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fileLength
fileLength(
S_name
)
=> x_size | 0
Description
Determines the number of bytes in a file.
A directory is viewed just as a file in this case. Uses the current SKILL path if a relative path
is given. Note that a path which is anchored to current directory, for example, ./, ../,or../
../.., etc., is not considered as a relative path.
Arguments
S_name Name of the file you want the size of.
Value Returned
x_size Number of bytes in the S_name file.
0 The file exists but is empty. Signals an error if the named file
does not exist.
Example
fileLength("/tmp") => 1024
Return value is system-dependent.
fileLength("~/test/out.1") => 32157
Assuming the named file exists and is 32157 bytes long.
Reference
isDir, isFile, isFileName
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fileSeek
fileSeek(
p_port
x_offset
x_whence
)
=> t | nil
Description
Sets the position for the next operation to be performed on the file opened on a port. The
position is specified in bytes.
Arguments
p_port Port associated with the file.
x_offset Number of bytes to move forward (or backward with negative
argument).
x_whence Valid Values:
0 Offset from the beginning of the file.
1 Offset from current position of file pointer.
2 Offset from the end of the file.
Value Returned
t The operation was successfully completed.
nil The file does not exist or the position given is out of range for an
input file.
Example
Let the file test.data contain the single line of text:
0123456789 test xyz
p = infile("test.data") => port:"test.data"
fileTell(p) => 0
for(i 1 10 getc(p)) => t ; Skip first 10 characters
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fileTell(p) => 10
fscanf(p "%s" s) => 1 ; s = "test" now
fileTell(p) => 15
fileSeek(p 0 0) => t
fscanf(p "%d" x) => 1 ; x = 123456789 now
fileSeek(p 6 1) => t
fscanf(p "%s" s) => 1 ; s = "xyz" now
Reference
fileTell, isDir, isFile, isFileName
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fileTell
fileTell(
p_port
)
=> x_offset
Description
Returns the current offset in bytes for the file opened on a port.
Arguments
p_port Port associated with the file.
Value Returned
x_offset Current offset (from the beginning of the file) in bytes for the file
opened on p_port.
Example
Let the file test.data contain the single line of text:
0123456789 test xyz
p = infile("test.data") => port:"test.data"
fileTell(p) => 0
for(i 1 10 getc(p)) => t ; Skip first 10 characters
fileTell(p) => 10
fscanf(p "%s" s) => 1 ;s = "test" now
fileTell(p) => 15
Reference
infile, isFile, fileSeek, outfile
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fileTimeModified
fileTimeModified(
t_filename
)
=> x_time | nil
Description
Gets the time a given file was last modified.
The return value is an internal, numeric, representation of the time the named file was last
modified (for example, the number of 1/100 seconds from January 1, 1970). The actual
number, which is system-dependent, is derived from the underlying UNIX system.
Arguments
t_filename Name of a file.
Value Returned
x_time Last time t_filename was modified.
nil No file with the given name was found.
Example
fileTimeModified( "~/.cshrc" )
=> 787435470
Reference
getCurrentTime, timeToString, timeToTm
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fix
fix(
n_arg
)
=> x_result
Description
Returns the largest integer not larger than the given argument.
This function is equivalent to floor. See also
“Type Conversion Functions (fix and float)” in
the SKILL Language User Guide.
Arguments
n_arg Any number.
Value Returned
x_result The largest integer not greater than n_arg. If an integer is given
as an argument, it returns the argument.
Example
fix(1.9) => 1
fix(-5.6) => -6
fix(100) => 100
Reference
ceiling, fixp, floor, round
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fixp
fixp(
g_value
)
=> t | nil
Description
Checks if an object is an integer, that is, a fixed number.
The suffix pis usually added to the name of a function to indicate that it is a predicate function.
This function is equivalent to integerp.
Arguments
g_value Any SKILL object.
Value Returned
t If g_value is an integer, a data type whose internal name is
fixnum.
nil If g_value is not an integer.
Example
fixp(3) => t
fixp(3.0) => nil
Reference
fix, float, floatp, integerp
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float
float(
n_arg
)
=> f_result
Description
Converts a number into its equivalent floating-point number.
Arguments
n_arg Integer to be converted to floating-point. If you give a floating-
point number as an argument, it returns the argument
unchanged.
Value Returned
f_result A floating-point number.
Example
float(3) => 3.0
float(1.2) => 1.2
Reference
fix, fixp, floatp
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floatp
floatp(
g_value
)
=> t | nil
Description
Checks if an object is a floating-point number. Same as realp.
The suffix pis usually added to the name of a function to indicate that it is a predicate function.
Arguments
g_value Any SKILL object.
Value Returned
t If g_value is a floating-point number, a data type whose
internal name is flonum.
nil If g_value is not a floating-point number.
Example
floatp(3) => nil
floatp(3.0) => t
Reference
fix, fixp, float, realp
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floor
floor(
n_number
)
=> x_integer
Description
Returns the largest integer not larger than the given argument.
Arguments
n_number Any number.
Value Returned
x_integer Largest integer not larger than n_number.
Example
(floor -4.3) => -5
(floor 3.5) => 3
Reference
ceiling, fix, round, truncate
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for
for(
s_loopVar
x_initialValue
x_finalValue
g_expr1
[ g_expr2 ... ]
)
=> t
Description
Evaluates the sequence g_expr1, g_expr2 ... for each loop variable value, beginning with
x_initialValue and ending with x_finalValue. This is a syntax form.
First evaluates the initial and final values, which set the initial value and final limit for the local
loop variable named s_loopVar. Both x_initialValue and x_finalValue must be
integer expressions. During each iteration, the sequence of expressions g_expr1,
g_expr2 ... is evaluated and the loop variable is then incremented by one. If the loop
variable is still less than or equal to the final limit, another iteration is performed. The loop
terminates when the loop variable reaches a value greater than the limit. The loop variable
must not be changed inside the loop. It is local to the for loop and would not retain any
meaningful value upon exit from the for loop.
Arguments
s_loopVar Name of the local loop variable that must not be changed inside
the loop.
x_initialValue Integer expression setting the initial value for the local loop
variable.
x_finalValue Integer expression giving final limit value for the loop.
g_expr1 Expression to evaluate inside loop.
g_expr2 Additional expression(s) to evaluate inside loop.
Value Returned
t This construct always returns t.
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forall
forall(
s_formalVar
l_valueList
g_predicateExpr )
=> t / nil
forall(
s_key
o_table
g_predicateExpr
)
=> t | nil
Description
Checks if g_predicateExpr evaluates to non-nil for every element in l_valueList.
This is a syntax form.
Verifies that an expression remains true for every element in a list. The forall function can
also be used to verify that an expression remains true for every key/value pair in an
association table. The syntax for association table processing is provided in the second
syntax statement.
Arguments
s_formalVar Local variable usually referenced in g_predicateExpr.
l_valueList List of elements that are bound to s_formalVar one at a time.
g_predicateExpr A SKILL expression that usually uses the value of
s_formalVar.
s_key Key portion of the table entry.
o_table Association table containing the entries to be processed.
Value Returned
t If g_predicateExpr evaluates to non-nil for every element
in l_valueList or for every key in an association table.
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nil Otherwise.
Example
forall( x '(1 2 3 4) (x > 0) )=> t
forall( x '(1 2 3 4) (x < 4) )=> nil
forall(key myTable (and (stringp key)(stringp myTable[key])))
=> t
Returns t if each key and its value in the association table are of the type string.
Reference
exists
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foreach
foreach(
s_formalVar
g_exprList
g_expr1
[ g_expr2 ... ]
)
=> l_valueList / l_result
foreach(
(
s_formalVar1...
s_formalVarN
)
g_exprList1...
g_exprListN
g_expr1
[ g_expr2 ... ]
)
=> l_valueList / l_result
foreach(
s_formalVar
g_exprTable
g_expr1
[ g_expr2 ... ]
)
=> o_valueTable | l_result
Description
Evaluates one or more expressions for each element of a list of values. This is a syntax form.
foreach( s_formalVar g_exprList g_expr1 [ g_expr2 ... ] )
=> l_valueList / l_result
The first syntax form evaluates g_exprList, which returns a list l_valueList. It then
assigns the first element from l_valueList to the formal variable s_formalVar and
executes the expressions g_expr1, g_expr2 ... in sequence. The function then
assigns the second element from l_valueList and repeats the process until
l_valueList is exhausted.
foreach( ( s_formalVar1...s_formalVarN ) g_exprList1... g_exprListN g_expr1 [
g_expr2 ... ] )
=> l_valueList / l_result
The second syntax form of foreach can iterate over multiple lists to perform vector
operations. Instead of a single formal variable, the first argument is a list of formal variables
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followed by a corresponding number of expressions for value lists and the expressions to be
evaluated.
foreach( s_formalVar g_exprTable g_expr1 [ g_expr2 ... ])
=> o_valueTable / l_result
The third syntax form of foreach can be used to process the elements of an association
table. In this case, s_formalVar is assigned each key of the association table one by one,
and the body expressions are evaluated each iteration. The syntax for association table
processing is provided in this syntax statement.
Arguments
s_formalVar Name of the variable.
s_mappingFunction One of map, mapc, mapcan, mapcar, or maplist.
g_exprList Expression whose value is a list of elements to assign to the
formal variable s_formalVar.
g_expr1, g_expr2 Expressions to execute.
g_exprTable Association table whose elements are to be processed.
Value Returned
l_valueList Value of the second argument, g_exprList.
l_result The result of the last expression evaluated.
o_valueTable Value of g_exprTable.
Example
foreach( x '(1 2 3 4) println(x))
1 ; Prints the numbers 1 through 4.
2
3
4
=> (1 2 3 4) ; Returns the second argument to foreach.
The next example shows foreach accessing an association table and printing each key and
its associated data.
foreach(key myTable printf("%L : %L\n" key myTable[key]))
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Example with more than one loop variable:
(foreach (x y) '(1 2 3) '(4 5 6) (println x+y))
5
7
9
=> (1 2 3)
Reference
mapc, mapcar, mapcan, forall, case, caseq
Errors and Warnings
The error messages from foreach might at times appear cryptic because some foreach
forms get expanded to call the mapping functions mapc, mapcar, mapcan, and so forth.
Advanced Usage
The foreach function typically expands to call mapc; however, you can also request that a
specific mapping function be applied by giving the name of the mapping function as the first
argument to foreach. Thus, foreach can be used as an extremely powerful tool to
construct new lists.
Note: Mapping functions are not accepted when this form is applied to association tables.
foreach( mapcar x '(1 2 3) (x >1))=> (nil t t)
foreach( mapcan x '(1 2 3) if((x > 1) ncons(x))) => (2 3)
foreach( maplist x '(1 2 3) length(x)) => (3 2 1)
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fprintf
fprintf(
p_port
t_formatString
[ g_arg1 ... ]
)
=> t
Description
Writes formatted output to a port.
The fprintf function writes formatted output to the port given as the first argument. The
optional arguments following the format string are printed according to their corresponding
format specifications.
printf is identical to fprintf except that it does not take the p_port argument and the
output is written to poport.
Output is right justified within a field by default unless an optional minus sign “-” immediately
follows the % character, which will then be left justified. To print a percent sign, you must use
two percent signs in succession. You must explicitly put \n in your format string to print a
newline character and \t for a tab.
Common Output Format Specifications
Format
Specification
Type(s) of
Argument
Prints
%d fixnum Integer in decimal radix
%o fixnum Integer in octal
%x fixnum Integer in hexadecimal
%f flonum Floating-point number in the style
[-]ddd.ddd
%e flonum Floating-point number in the style
[-]d.ddde[-]ddd
%g flonum Floating-point number in style f or e, whichever
gives full precision in minimum space
%s string, symbol Prints out a string (without quotes) or the print
name of a symbol
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The t_formatString argument is a conversion control string containing directives listed
in the table above. The %L, %P, and %B directives ignore the width and precision fields.
%[-][width][.precision]conversion_code
[-] = left justify
[width] = minimum number of character positions
[.precision] = number of characters to be printed
conversion_code
Arguments
p_port Output port to write to.
t_formatString Characters to be printed verbatim, intermixed with format
specifications prefixed by the % sign.
g_arg1 The arguments following the format string are printed according
to their corresponding format specifications.
Value Returned
t Prints the formatted output and returns t.
Example
p = outfile("power.out")
=> port:"power.out"
for(i 0 15 fprintf(p "%20d %-20d\n" 2**i 3**i))
=> t
close( p)
%c string, symbol The first character
%n fixnum, flonum Number
%L list Default format for the data type
%P list Point
%B list Box
Common Output Format Specifications
Format
Specification
Type(s) of
Argument
Prints
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fscanf, scanf, sscanf
fscanf(
p_inputPort
t_formatString
[ s_var1 ... ]
)
=> x_items | nil
scanf(
t_formatString
[ s_var1 ... ]
)
=> x_items | nil
sscanf(
t_sourceString
t_formatString
[ s_var1 ... ]
)
=> x_items | nil
Description
The only difference between these functions is the source of input. fscanf reads input from
a port according to format specifications and returns the number of items read in. scanf
takes its input from piport implicitly. scanf only works in standalone SKILL when the
piport is not the CIW. sscanf reads its input from a string instead of a port.
The results are stored into corresponding variables in the call. The fscanf function can be
considered the inverse function of the fprintf output function. The fscanf function returns
the number of input items it successfully matched with its format string. It returns nil if it
encounters an end of file.
The maximum size of any input string being read as a string variable for fscanf is currently
limited to 8K. Also, the function lineread is a faster alternative to fscanf for reading SKILL
objects.
If an error is found while scanning for input, only those variables read before the error will be
assigned.
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The common input formats accepted by fscanf are summarized below.
Arguments
p_inputPort Input port fscanf reads from. The input port cannot be the CIW
for fscanf.
t_sourceString Input string for sscanf.
t_formatString Format string to match against in the reading.
s_var1 Name of variable to store results of read.
Value Returned
x_items The number of input items it successfully read in. As a side-
effect, the items read in are assigned to the corresponding
variables specified in the call.
nil It encounters an end of file.
Example
fscanf( p "%d %f" i d )
Scans for an integer and a floating-point number from the input port p and stores the values
read in the variables i and d, respectively.
Assume a file testcase with one line:
hello 2 3 world
Common Input Format Specifications
Format
Specification
Type(s) of
Argument
Scans for
%d fixnum An integer
%f flonum A floating-point number
%s string A string (delimited by spaces) in the input
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funcall
funcall(
slu_func
[ arg ... ]
)
=> g_result
Description
Applies the given function to the given arguments.
The first argument to funcall must be either the name of a function or a lambda/
nlambda/macroexpression or a function object. The rest of the arguments are to be passed
to the function.
The arguments arg ...are bound to the formal arguments of s1u_func according to the
type of function. For lambda functions the length of arg should match the number of formal
arguments, unless keywords or optional arguments exist. For nlambdaand macrofunctions,
arg are bound directly to the single formal parameter of the function.
Note: If s1u_func is a macro, funcall evaluates it only once, that is, it expands it and
returns the expanded form, but does not evaluate the expanded form again (as eval does).
Arguments
slu_func Name of the function.
arg Arguments to be passed to the function.
Value Returned
g_result The result of applying the function to the given arguments.
Example
funcall( 'plus 1 2 ) ; Apply plus to its arguments.
=> 3
procedure( sum3(x y z) funcall( 'plus x y z)
=> sum3 ;Define a procedure
sum3(1 2 3)
=> 6
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funobj
funobj(
x_id
)
=> U_functionObject
Description
Returns the function object designated by the given object ID.
It signals an error if the argument is not a valid function object ID.
Arguments
x_id The ID of a function object that appears in its print
representation.
Value Returned
U_functionObject Function object whose ID is x_id. An error is signaled if no
match is found.
Example
F = lambda( ( x y ) x+y ) => funobj:0x1e3688
eq( funobj( 0x1e3688 ) F ) => t
This example assigns a function object to the variable F. Extract the ID from the print
representation by inspection and pass it to the funobj function. Using the eq function
demonstrates that the return value is the original function object.
Reference
envobj
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gc
gc(
[ t_string ]
)
=> nil
Description
Forces a garbage collection. This function is also called by the system.
Garbage collection (gc) refers to the process in which SKILL locates storage cells that are no
longer needed (thus the term garbage) and recycles them by putting them back on the free
storage list. Garbage collection is also called by the system. Garbage collection is transparent
to SKILL users and to users of applications built on top of SKILL.
You can turn on the printing of garbage collection messages by setting the _gcprint
variable to t (that is, _gcprint=t). Garbage collection can be turned off at any time by
setting the gcdisable variable to t. To enable garbage collection again, you can restore
gcdisable to its previous value. You can force a garbage collection at any time by calling
the gc function.
Caution
Because some applications turn off garbage collection during their
execution, you should be careful about enabling it. Corrupted data can
result.
Arguments
t_string File into which additional information is dumped.
Value Returned
nil Always returns nil.
Example
gc( ) => nil
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gensym
gensym(
[ S_arg ]
)
=> s_result
Description
Returns a new symbol based on the input argument.
The new symbol’s print name is the result of concatenating the printed representation of the
argument, or “G” if no argument is given, and the printed (decimal) representation of a
number. The returned new symbol is unique in the sense that it does not exist at the time this
function is called.
Arguments
S_arg String or symbol to be concatenated into a new symbol. If not
supplied, the default value is G.
Value Returned
s_result New unique symbol.
Example
gensym() => G5
gensym("test") => test6
test7 = 10 => 10 ;test7 exists now.
gensym('test) => test8 ;test7 is skipped.
gensym() == gensym() => nil ;Always returns nil.
Reference
concat, symbolp, symeval, symstrp
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geqp
geqp(
n_num1
n_num2
)
=> t | nil
Description
This predicate function checks if the first argument is greater than or equal to the second
argument. Prefix form of the >= operator.
Arguments
n_num1 Number to be checked.
n_num2 Number against which n_num1 is checked.
Value Returned
t n_num1 is greater than or equal to n_num2.
nil n_num1 is less than n_num2.
Example
geqp(2 2) => t
geqp(-2 2) => nil
geqp(3 2.2) => t
Reference
greaterp, leqp, lessp
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get
get(
sl_id
S_name
)
=> g_result | nil
Description
Returns the value of a property in a property list (including disembodied property list),
association table, structure, and database object.
Used in conjunction with putprop, where putprop stores the property and get retrieves it.
Arguments
sl_id Symbol or disembodied property list.
S_name Name of the property you want the value of.
Value Returned
g_result Value of s_name in the sl_id property list.
nil The named property does not exist.
Example
putprop( 'chip 8 'pins ) => 8
Assigns the property pins to a value of 8 to the symbol chip.
get( 'chip 'pins ) => 8
chip.pins => 8
x = '(nil a 3 b 4) ;a disembodied property list
x->a => 3
get(x 'a) => 3
Reference
plist, putprop
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get_filename
get_filename(
p_port
)
=> s_result
Description
Returns the file name of a port.
Arguments
p_port A port object.
Value Returned
x_result The file name of the port.
Examples
aPort => port:"inFile"
get_filename( aPort ) => "inFile"
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get_pname
get_pname(
s_arg
)
=> t_result
Description
Returns the print name of a symbol as a string.
This function is useful for converting symbols to strings. If you just want to print the name of
a symbol, you do not need to use this function. This function is equivalent to
symbolToString.
Arguments
s_arg A symbol.
Value Returned
t_result Print name of the symbol.
Example
get_pname( 'a ) => "a"
get_pname(concat("Cell_" 123)) => "Cell_123"
Reference
concat, get_string, stringToSymbol,symbolToString
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get_string
get_string(
S_arg
)
=> t_result
Description
Converts the argument to a string if it is a symbol. Otherwise it returns the string itself.
Arguments
S_arg String or symbol.
Value Returned
t_result Of the argument is a string, returns the argument itself. If the
argument is a symbol, returns the print name as a string.
Example
get_string('xyz) => "xyz"
get_string("xyz") => "xyz"
Reference
concat, get_pname, symbolToString
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getc
getc(
[ p_inputPort ]
)
=> s_char
Description
Reads and returns a single character from an input port. Unlike the C library, the getc and
getchar SKILL functions are totally unrelated.
The input port arguments for both gets and getc are optional. If the port is not given, the
functions take their input from piport.
Arguments
p_inputPort Input port; if not given, function defaults to piport.
Value Returned
s_char Single character from the input port in symbol form. If the
character returned is a non-printable character, its octal value is
stored as a symbol.
Example
In the following assume the file test1.data has its first line read as:
#This is the data for test1
p = infile("test1.data") => port:"test1.data"
getc(p) => \#
getc(p) => T
getc(p) => h
Reference
gets
SKILL Language Reference
SKILL Language Functions
August 2005 195 Product Version 06.40
getchar
getchar(
S_arg
x_index
)
=> s_char | nil
Description
Returns an indexed character of a string or the print name if the string is a symbol. Unlike the
C library, the getc and getchar SKILL functions are totally unrelated.
Arguments
S_arg Character string or symbol.
x_index Number corresponding to an indexed point in S_arg.
Value Returned
s_char Single character symbol corresponding to the character in
S_arg indexed by x_index.
nil If x_index is less than 1 or greater than the length of the string.
Example
getchar("abc" 2) => b
getchar("abc" 4) => nil
Reference
nindex, parseString, strlen, substring
SKILL Language Reference
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August 2005 196 Product Version 06.40
getCurrentTime
getCurrentTime(
)
=> t_timeString
Description
Returns a string representation of the current time.
Arguments
None.
Value Returned
t_timeString Current time in the form of a string. The format of the string is
month day hour:minute:second year.
Example
getCurrentTime( )=> "Jan 26 18:15:18 1994"
This format is also used by the compareTime function.
Reference
compareTime
SKILL Language Reference
SKILL Language Functions
August 2005 197 Product Version 06.40
getd
getd(
s_functionName
)
=> g_definition | nil
Description
Returns the function binding for a function name.
Note: This function is not needed in SKILL++ because functions are treated as regular
values. Therefore you can simply use variable reference syntax to access any function
binding.
Arguments
s_functionName Name of the function.
Value Returned
g_definition If the function is defined in SKILL, returns the function object that
the procedure function associates with a symbol.
If the function is primitive, the binary definition is printed (see
example below).
nil No function definition exists.
Example
getd( 'alias ) => nlambda:alias
The function is primitive.
getd( 'edit ) => funobj:0x24b478
The function is written in SKILL.
Reference
alias, bcdp, putd
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August 2005 198 Product Version 06.40
getDirFiles
getDirFiles(
S_name
)
=> l_strings
Description
Returns a list of the names of all files and directories, including . and .., in a directory.
Uses the current SKILL path for relative paths. Note that a path which is anchored to current
directory, for example, ./, ../, or ../../.., etc., is not considered as a relative path.
Arguments
S_name Name of the directory in either string or symbol form.
Value Returned
l_strings List of names of all files and directories in a given directory name
(including . and ..).
Signals an error if the directory does not exist or is inaccessible.
Example
getDirFiles(car(getInstallPath()))=> ("." ".." "bin" "cdsuser" "etc" "group"
"include" "lib" "pvt" "samples" "share" "test" "tools" "man" "local" )
Reference
getInstallPath, getSkillPath, isDir
SKILL Language Reference
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getFnWriteProtect
getFnWriteProtect(
s_name
)
=> t | nil
Description
Checks if the given function is write-protected.
The value is t if s_name is write-protected; nil otherwise.
Arguments
s_name Name of the function.
Value Returned
t The function is write protected.
nil The function is not write protected.
Signals an error if the function is not defined.
Example
getFnWriteProtect( 'strlen ) => t
Reference
getd, setFnWriteProtect
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SKILL Language Functions
August 2005 200 Product Version 06.40
getFunType
getFunType(
u_functionObject
)
=> s_functionObject_type
Description
Returns a symbol denoting the function type for a given function object.
Possible function types include lambda, nlambda, macro, syntax, or primop.
Arguments
u_functionObject A function object.
Value Returned
s_functionObject_type
Possible return values include lambda, nlambda, macro,
syntax, or primop.
Example
getFunType( getd( 'sin )) => lambda
getFunType( lambda( (x y) x+y )) => lambda
getFunType( getd( 'breakpt )) => nlambda
getFunType( getd( 'if )) => syntax
getFunType( getd( 'plus )) => primop
Reference
defmacro, getd, lambda, mprocedure, nprocedure - SKILL mode only, procedure
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getInstallPath
getInstallPath(
)
=> l_string
Description
Returns the absolute path of the Cadence DFII installation directory where the DFII products
are installed on your system as a list of a single string.
Arguments
None.
Value Returned
l_string Returns the installation path as a list of a single string.
Example
getInstallPath() => ("/usr5/cds/5.0")
Reference
getSkillPath, getWorkingDir, prependInstallPath, cdsGetInstPath
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getLogin
getLogin(
)
=> t_loginName
Description
Returns the user’s login name as a string.
Arguments
None.
Value Returned
t_loginName Returns the user’s login name as a string.
Example
getLogin
=> "fred"
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getPrompts
getPrompts(
)
=> l_strings
Description
Returns the current values of the first level and second level prompt text strings, respectively.
The first prompt text string is the first level prompt that represents the topmost top-level
prompt, while the second one indicates the second level prompt which is used whenever a
nested top-level is entered.
Arguments
None.
Value Returned
l_strings The current values of the first level and second level prompt text
strings. The result is a list where the first element is the first level
prompt and the second element is the second level prompt
specified by setPrompts.
Example
skill> getPrompts()
("> " "<%d> ")
CIW> getPrompts()
("> " "> ")
Default prompts for the SKILL interpreter and CIW, respectively.
Reference
setPrompts
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getq
getq(
sl_id
S_name
)
=> g_result | nil
getq(
sl_id->s_name
)
=> g_result | nil
Description
Returns the value of a property in a property list. Same as get except that the second
argument is not evaluated. This is a syntax form.
Used in conjunction with putprop, where putprop stores the property and getq retrieves it.
Arguments
sl_id Symbol or disembodied property list.
S_name Name of the property you want the value of.
Value Returned
g_result Value of s_name in the sl_id property list.
nil The named property does not exist.
Example
putprop( 'chip 8 'pins ) => 8
Assigns the property pins to a value of 8 to the symbol chip.
getq( 'chip pins ) => 8
chip.pins => 8
chip1 = list(nil 'pins 10) => (nil pins 10)
chip1->pins => 10
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getqq
getqq(
s_id
S_name
)
=> g_result | nil
getqq(
sl_id.s_name
)
=> g_result | nil
Description
Returns the value of a property in a symbol’s property list. Same as get except that neither
argument is evaluated. This is a syntax form.
Used in conjunction with putprop, where putpropstores the property and getqq retrieves
it.
Arguments
s_id Symbol to get a property from.
S_name Name of the property you want the value of.
Value Returned
g_result Value of the property S_name in the property list of s_id.
nil The named property does not exist.
Example
putprop( 'chip 8 'pins ) => 8
Assigns the property pins to a value of 8 to the symbol chip.
getqq( chip pins ) => 8
chip.pins => 8
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getTempDir
getTempDir(
)
=> t_TempDir
Description
Returns the system temp directory as a string.
Arguments
None.
Value Returned
t_TempDir The name of your current temp directory.
Example
getTempDir() => "/tmp"
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gets
gets(
s_variableName
[ p_inputPort ]
)
=> t_string |nil
Description
Reads a line from the input port and stores the line as a string in the variable. This is a macro.
The string is also returned as the value of gets. The terminating newline character of the line
becomes the last character in the string.
Arguments
s_variableName Variable to store input string in.
p_inputPort Name of input port; piport is used if none is given.
Value Returned
t_string Returns the input string when successful.
nil When EOF is reached.
s_variableName stores the last value returned (that is, nil).
Example
Assume the test1.data file has the following first two lines:
#This is the data for test1
0001 1100 1011 0111
p = infile("test1.data") => port:"test1.data"
gets(s p) => "#This is the data for test1\n"
gets(s p) => "0001 1100 1011 0111\n"
s => "0001 1100 1011 0111\n"
Reference
getc, getchar, infile
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getShellEnvVar
getShellEnvVar(
t_UnixShellVariableName
)
=> t_value | nil
Description
Returns the value of a UNIX environment variable, if it has been set.
Arguments
t_UnixShellVariableName
Name of the UNIX shell environment variable.
Value Returned
t_value Value of named UNIX environment variable.
nil No environment variable with the given name has been set.
Example
getShellEnvVar("SHELL") => "/bin/csh"
Returns the current value of the SHELL environment variable.
Reference
setShellEnvVar
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getSkillPath
getSkillPath(
)
=> l_strings | nil
Description
Returns the current SKILL path.
The SKILL path is used in resolving relative paths for some SKILL functions. See
"/O and File
Handling" in the SKILL Language User Guide.
Arguments
None.
Value Returned
l_strings Directory paths from the current SKILL path setting. The result is
a list where each element is a path component as specified by
setSkillPath.
nil The last call to setSkillPath gave nil as its argument.
Example
setSkillPath('("." "~" "~/cpu/test1"))
=> ("~/cpu/test1")
getSkillPath() => ("." "~" "~/cpu/test1")
The example below shows how to add a directory to the beginning of your search path
(assuming a directory “~/lib”).
setSkillPath(cons("~/lib" getSkillPath()))
=> ("~/lib" "~/cpu/test1")
getSkillPath()
=> ("~/lib" "." "~" "~/cpu/test1")
Reference
setSkillPath
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getSkillVersion
getSkillVersion(
)
=> t_version
Description
Returns the version of the SKILL that is currently running.
Arguments
None.
Value Returned
t_version Version of the SKILL that is currently running.
Example
getSkillVersion()
=> "SKILL04.20"
Reference
getVersion
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getVarWriteProtect - SKILL mode only
getVarWriteProtect(
s_name
)
=> t | nil
Description
Checks if a variable is write-protected. Does not work in SKILL++ mode. In SKILL++ mode,
use getFnWriteProtect instead.
Arguments
s_name Name of the variable to check.
Value Returned
t The variable is write-protected.
nil Otherwise.
Example
x = 5
getVarWriteProtect( 'x ) => nil
Returns nil if the variable x is not write protected.
Reference
getFnWriteProtect, setVarWriteProtect - SKILL mode only
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getVersion
getVersion(
[ g_opt ]
)
=> t_version
Description
Returns the version number of the Cadence software you are currently using.
Arguments
g_opt Optional argument. If this argument is given, the subversion
number of the Cadence software currently using is returned. By
default, the full version number, including hotfix version, of the
Cadence software currently using is returned.
Value Returned
t_version String identifying the version/subversion of the program you are
running.
Example
getVersion() => "@(#)$CDS: icfb.exe version 5.0.0 08/14/2002 17:52 (cds11612) $"
getVersion( ’subVer ) => "sub-version 5.0.0.36.72"
Reference
getSkillVersion
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getWarn
getWarn(
)
=> t_warning
Description
Returns the buffered warning if it has not already been printed.
Arguments
None.
Value Returned
t_warning The warning message that would have been printed if it had not
been intercepted by the call to getWarn.
Example
procedure( testWarn( @key ( getLastWarn nil ) )
warn("This is warning %d\n" 1 ) ;;; print previous warning
warn("This is warning %d\n" 2 ) ;;; and buffer new one.
warn("This is warning %d\n" 3 )
when( getLastWarn
thrownAwayWarn = getWarn( ) ;;; throw away last warning
nil ;;; return nil
) ; when
) ; procedure
The testWarn function intercepts the last warning message and stores it in a global variable
if t is passed in, and lets the system print all the warnings if nil is given as an argument.
Use of the getWarn( ) function makes it possible to throw away a warning message, if desired.
testWarn( ?getLastWarn t)
=> nil
*WARNING* This is warning 1
*WARNING* This is warning 2
Returns nil. The system prints the first two warnings and the third is intercepted and stored
in global variable thrownAwayWarn.
testWarn( ?getLastWarn nil)
=> nil
*WARNING* This is warning 1
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*WARNING* This is warning 2
*WARNING* This is warning 3
Returns nil. The system prints all the queued warnings.
Note that the return value may be interleaved with the warning message output. The following
example shows how the actual output can appear in the CIW.
testWarn( ?getLastWarn t)
*WARNING* This is warning 1
*WARNING* This is warning 2
=> nil
testWarn( ?getLastWarn nil)
*WARNING* This is warning 1
*WARNING* This is warning 2
=> nil
*WARNING* This is warning 3
Reference
print, warn
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August 2005 217 Product Version 06.40
getWorkingDir
getWorkingDir(
)
=> t_currentDir
Description
Returns the current working directory as a string.
The result is put into a ~/prefixed form if possible by testing for commonality with the
current user’s home directory. For example, ~/test would be returned in preference to /
usr/mnt/user1/test, assuming that the home directory for user1 is /usr/mnt/user1
and the current working directory is /usr1/mnt/user1/test.
Arguments
None.
Value Returned
t_currentDir The name of your current working directory.
Example
getWorkingDir() => "~/project/cpu/layout"
Reference
changeWorkingDir
SKILL Language Reference
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August 2005 218 Product Version 06.40
go
go(
s_label
)
Description
Transfers control to the statement following the label argument. This is a syntax form.
The go statement is only meaningful when it is used inside a prog statement. Control can be
transferred to any labelled statement inside any progs that contain the go statement, but
cannot be transferred to labelled statements in a prog that is not active at the time the go
statement is executed. Generally, using go is considered poor programming style when
higher level control structures such as foreach and while can be used.
Arguments
s_label Label you want to transfer control to inside a prog.
Value Returned
None.
Example
The following example demonstrates how to use the go function form in a simple loop
structure.
procedure( testGo( data )
prog( ()
start
print( car( data ))
data = cdr( data )
if( data go( start )) ; go statement to jump to start.
))
testGo( '(a b c))
abc ; Prints the variable data.
=> nil ; Returns nil.
Reference
prog, foreach, return, while
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August 2005 219 Product Version 06.40
greaterp
greaterp(
n_num1
n_num2
)
=> t | nil
Description
This predicate function checks if the first argument is greater than the second argument.
Prefix form of the > operator.
Arguments
n_num1 Number to be checked.
n_num2 Number against which n_num1 is checked.
Value Returned
t n_num1 is greater than n_num2.
nil n_num1 is less than or equal to n_num2.
Example
greaterp(2 2) => nil
greaterp(-2 2) => nil
greaterp(3 2.2) => t
Reference
geqp, leqp, lessp
SKILL Language Reference
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August 2005 220 Product Version 06.40
help
help(
[ S_name ]
)
=> t | nil
Description
Retrieves and prints the cdsFinder documentation strings for the given function name (a
symbol). If the given name is a string, it is interpreted as a regular expression, and the entire
cdsFinder database is searched for functions whose name or documentation string contains
or matches the given string. Help is an nlambda function.
Arguments
S_name Name to search for.
Value Returned
t The given function name is found in the cdsFinder.
nil No match is found for S_name.
Example
help nonexist
=> nil
help scanf
Prints the following and returns t.
fscanf( p_inputPort t_formatString [s_var1 ...] )
scanf( t_formatString [s_var1 ...] )
sscanf( t_sourceString t_formatString [s_var1 ...] )
The only difference between these functions is the source of input. fscanf reads input from
a port according to format specifications and returns the number of items read in. scanf
takes its input from piport implicitly. scanf only works in standalone SKILL when the piport
is not the CIW. sscanf reads its input from a string instead of a port.
=> t
help println
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Prints the following and returns t.
println( g_value [p_outputPort] ) => nil
Prints a SKILL object using the default format for the data type of the value, then prints a
newline character.
=> t
help "read"
Prints the following and returns t.
fscanf, scanf, sscanf, getWarn, infile, instring, ipcReadProcess,
ipcWaitForProcess, isReadable, lineread, linereadstring, load, loadstring,
outfile, pp, putpropq, putpropqq, read, readTable, readstring
=> t
help "match nowhere"
=> nil
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August 2005 222 Product Version 06.40
if
if(
g_condition
g_thenExpression
[ g_elseExpression ]
)
=> g_result
if(
g_condition
then g_thenExpr1 ...
[ else g_elseExpr1 ... ]
)
=> g_result
Description
Selectively evaluates two groups of one or more expressions. This is a syntax form.
if( g_condition g_thenExpression [ g_elseExpression ] )
=> g_result
The if form evaluates g_condition, typically a relational expression, and executes
g_thenExpression if the condition is true (that is, its value is non-nil); otherwise,
g_elseExpression is executed. The value returned by if is the value of the
corresponding expression evaluated. The if form can therefore be used to evaluate
expressions conditionally.
if( g_condition then g_thenExpr1 ... [ else g_elseExpr1 ... ] )
=> g_result
The second form of if uses the keywords then and else to group sequences of
expressions for conditional execution. If the condition is true, the sequence of expressions
between then and else (or the end of the if form) is evaluated, with the value of the last
expression evaluated returned as the value of the form. If the condition is nil instead, the
sequence of expressions following the else keyword (if any) is evaluated instead. Again, the
value of the last expression evaluated is returned as the value of the form.
Arguments
g_condition Any SKILL expression.
g_thenExpression Any SKILL expression.
g_elseExpression Any SKILL expression.
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Value Returned
g_result The value of g_thenExpression if g_condition has a
non-nil value. The value of g_elseExpression is returned
if the above condition is not true.
Example
x = 2
if( (x > 5) 1 0)
=> 0 ; Returns 0 because x is less than 5.
a = "polygon"
if( (a == "polygon") print(a) )
"polygon" ; Prints the string polygon.
=> nil ; Returns the result of print.
x = 5
if( x "non-nil" "nil" )
=> "non-nil" ; Returns "non-nil" because x was not
; nil. If x was nil then "nil" would be
; returned.
x = 7
if( (x > 5) then 1 else 0)
=> 1 ; Returns 1 because x is greater than 5.
if( (x > 5)
then println("x is greater than 5")
x + 1
else print("x is less ")
x - 1)
x is greater than 5 ; Printed if x was 7.
=> 8 ; Returned 8 if x was 7.
Reference
cond, for, foreach, unless, while
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August 2005 224 Product Version 06.40
importSkillVar - SKILL++ mode
importSkillVar(
s_variable ...
)
=> nil
Description
Tells the compiler that the given variable names should be treated as SKILL global variables
in SKILL++ code.
All global SKILL functions are automatically accessible from SKILL++ code, but not the SKILL
variables. This form tells the compiler that the given variable names should be treated as
SKILL global variables in SKILL++ code.
This function has no effect if there is already a SKILL++ global variable of the same name
defined. Also remember that local variables can use the same name and always take
precedence.
Note: This only means that the variables will be accessed as SKILL globals, NOT that they
will follow SKILL’s dynamic scope rule in SKILL++ code.
Arguments
s_variable Variable to be treated as SKILL global variables in SKILL++
code.
Value Returned
nil Always returns nil. This function is for side-effect only.
Example
> q = 1
=> 1
> toplevel 'ils
ILS-<2> q
*Error* eval: unbound variable - q
ILS-<2> importSkillVar( q )
=> 1
ILS-<2> q
=> 1
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This example shows assigning a value to the global variable q in SKILL mode and then
importing the variable into SKILL++.
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index
index(
t_string1
S_string2
)
=> t_result | nil
Description
Returns a string consisting of the remainder of string1 beginning with the first occurrence
of string2.
Arguments
t_string1 String to search for the first occurrence of S_string2.
S_string2 String to search for in t_string1.
Value Returned
t_result If S_string2 is found in t_string1, returns a string equal
to the remainder of t_string1 that begins with the first
character of S_string2.
nil If S_string2 is not found.
Example
index( "abc" 'b ) => "bc"
index( "abcdabce" "dab" ) => "dabce"
index( "abc" "cba" ) => nil
index( "dandelion" "d") => "dandelion"
Reference
rindex, strcmp, strncmp
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infile
infile(
S_fileName
)
=> p_inport | nil
Description
Opens an input port ready to read a file. Always remember to close the port when you are
done.
The file name can be specified with either an absolute path or a relative path. In the latter
case, current SKILL path is used if it’s not nil. Note that a path which is anchored to current
directory, for example, ./, ../, or ../../.., etc., is not considered as a relative path.
Note: Always remember to close the port when you are done.
Arguments
S_fileName Name of the file to be read; it can be either a string or a symbol.
Value Returned
p_inport Port opened for reading the named file.
nil The file does not exist or cannot be opened for reading.
Example
in = infile("~/test/input.il") => port:"~/test/input.il"
If such a file exists and is readable.
infile("myFile") => nil
If myFile does not exist according to the current setting of the SKILL path or exists but is not
readable.
close(in) => t
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inportp
inportp(
g_obj
)
=> t | nil
Description
Checks if an object is an input port.
Note: An input port may be closed, so if inportp returns t, that does not guarantee a
successful read from the port.
Arguments
g_obj Any SKILL object.
Value Returned
t The given object is an input port.
nil Otherwise.
Example
(inportp piport) => t
(inportp poport) => nil
(inportp 123) => nil
Reference
outportp
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August 2005 230 Product Version 06.40
inScheme
inScheme(
g_form
)
=> g_result
Description
Evaluates a form as top-level SKILL++ code, disregarding the surrounding evaluation context.
Arguments
g_form Form to be evaluated as top-level SKILL++ code.
Value Returned
g_result Result of the evaluation.
Example
(inScheme
(define myVar 100)) => myVar
Defines a SKILL++ global variable, even if this code appears inside a SKILL file.
Reference
inSkill
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August 2005 231 Product Version 06.40
inSkill
inSkill(
g_form
)
=> g_result
Description
Evaluates a form as top-level SKILL code, disregarding the surrounding evaluation context.
Arguments
g_form Form to be evaluated as top-level SKILL code.
Value Returned
g_result Result of the evaluation.
Example
(inSkill
skillVar = 100) => 100
Sets a SKILL global variable, even if this code appears inside a SKILL++ file.
Reference
inScheme
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August 2005 232 Product Version 06.40
instring
instring(
t_string
)
=> p_port
Description
Opens a string for reading, just as infile would open a file.
An input port that can be used to read the string is returned. Always remember to close
the port when you are done.
Arguments
t_string Input string opened for reading.
Value Returned
p_port Port for the input string.
Example
s = "Hello World!" => "Hello World!"
p = instring(s) => port:"*string*"
fscanf(p "%s %s" a b) => 2
a => "Hello"
b => "World!"
close(p)=> t
Reference
gets, infile
SKILL Language Reference
SKILL Language Functions
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integerp
integerp(
g_obj
)
=> t | nil
Description
Checks if an object is an integer. This function is the same as fixp.
Arguments
g_obj Any SKILL object.
Value Returned
t The given object is an integer.
nil Otherwise.
Example
(integerp 123) => t
(integerp "123") => nil
Reference
fixp
SKILL Language Reference
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August 2005 234 Product Version 06.40
intToChar
intToChar(
x_ascii
)
=> s_char
Description
Returns the single-character symbol whose ASCII code is the given integer value.
Arguments
x_ascii ASCII code.
Value Returned
s_char Symbol of single-character whose ASCII code is x_ascii.
Example
intToChar( 66)
=> B
Reference
charToInt
SKILL Language Reference
SKILL Language Functions
August 2005 235 Product Version 06.40
isCallable
isCallable(
s_function
)
=> t | nil
Description
Checks if a function is defined or is autoloadable from a context.
Arguments
s_function Name of a function.
Value Returned
t The specified function is defined or is autoloadable.
nil The specified function is not defined or is not autoloadable.
Example
isCallable( 'car) => t
procedure( myFunction( x ) x+1)
isCallable('myFunction) => t
Reference
bcdp, getd, load, putd
SKILL Language Reference
SKILL Language Functions
August 2005 236 Product Version 06.40
isDir
isDir(
S_name
[ tl_path ]
)
=> t | nil
Description
Checks if a path exists and if it is a directory name.
When S_name is a relative path, the current SKILL path is used if it’s non-nil. Note that a
path which is anchored to current directory, for example, ./, ../,or../../.., etc., is not
considered as a relative path.
Arguments
S_name Path you want to check.
tl_path List of paths that overrides the SKILL path.
Value Returned
t The name exists and it is the name of a directory.
nil The name exists and is not the name of a directory or S_name
does not exist at all.
Example
isDir("DACLib") => t
isDir("triadc") => nil
Assumes DACLib is a directory and triadc is a file under the current working directory and
the SKILL path is nil.
isDir("test") => nil
Result if test does not exist.
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August 2005 238 Product Version 06.40
isExecutable
isExecutable(
S_name
[ tl_path ]
)
=> t | nil
Description
Checks if you have permission to execute a file or search a directory.
A directory is executable if it allows you to name that directory as part of your path in
searching files. It uses the current SKILL path for relative paths. Note that a path which is
anchored to current directory, for example, ./, ../,or../../.., etc., is not considered as
a relative path.
Arguments
S_name Name of the file or directory you want to check for execution/
search permission.
tl_path List of paths that overrides the SKILL path.
Value Returned
t If you have permission to execute the file or search the directory
specified by S_name.
nil The directory does not exist or you do not have the required
permissions.
Example
isExecutable("/bin/ls") => t
isExecutable("/usr/tmp") => t
isExecutable("attachFiles") => nil
Result if attachFiles does not exist or is non-executable.
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isFile
isFile(
S_name
[ tl_path ]
)
=> t | nil
Description
Checks if a file exists and that it is not a directory.
Identical to isFileName, except that directories are not viewed as (regular) files. Uses the
current SKILL path for relative paths. Note that a path which is anchored to current directory,
for example, ./, ../, or ../../.., etc., is not considered as a relative path.
Arguments
S_name Path you want to check.
tl_path List of paths that overrides the SKILL path.
Value Returned
t The S_name file exists.
nil The S_name file does not exist.
Example
isFile( "DACLib") => nil
Assumes DACLib is a directory and triadc is a file in the current working directory and the
SKILL path is nil. A directory is not viewed as a file in this case.
isFile( "triadc") => t
isFile( ".cshrc" list("." "~")) => t
Reference
isDir, isFileName, getSkillPath
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August 2005 241 Product Version 06.40
isFileEncrypted
isFileEncrypted(
S_name
)
=> t | nil
Description
Checks if a file exists and is encrypted.
Similar to isFile, except that it returns t only if the file exists and is encrypted. Uses the
current SKILL path for relative paths. Note that a path which is anchored to current directory,
for example, ./, ../, or ../../.., etc., is not considered as a relative path.
Arguments
S_name File you want to check.
Value Returned
t The S_name file exists and is encrypted.
nil The S_name file does not exist or is not encrypted.
Example
isFileEncrypted( "~/testfns.il") => nil
encrypt( "~/testfns.il" "~/testfns.ile")
isFileEncrypted( "~/testfns.ile") => t
Reference
encrypt, getSkillPath, isFile
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August 2005 242 Product Version 06.40
isFileName
isFileName(
S_name
[ tl_path ]
)
=> t | nil
Description
Checks if a file or directory exists.
The file name can be specified with either an absolute path or a relative path. In the latter
case, current SKILL path is used if it’s not nil. Only the presence or absence of the name is
checked. If found, the name can belong to either a file or a directory. isFileName differs
from isFile in this regard. Note that a path which is anchored to current directory, for
example, ./, ../, or ../../.., etc., is not considered as a relative path.
Arguments
S_name Path you want to check.
tl_path List of paths to override the SKILL path.
Value Returned
t The S_name path exists.
nil The S_name path does not exist.
Example
Suppose DACLib is a directory and triadc is a file in the current working directory and the
SKILL path is nil.
isFileName("DACLib") => t
A directory is just a special kind of file.
isFileName("triadc") => t
isFileName("triad1") => nil
Result if triad1 does not exist in current working directory.
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August 2005 244 Product Version 06.40
isInfinity
isInfinity(
f_flownum
)
=> t | nil
Description
Checks if the given flownum argument represents infinity (positive or negative).
Arguments
f_flownum A floating-point number.
Value Returned
t If f_flownum is infinity (positive or negative).
nil Otherwise.
Example
plus_inf = 2.0 * 1e999
isInfinity (plus_inf) => t
isInfinity (987.65) => nil
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August 2005 245 Product Version 06.40
isLargeFile
isLargeFile(
S_name
[ tl_path ]
)
=> t | nil
Description
Checks if a file is a large file (with size greater than 2GB).
The file name can be specified with either an absolute path or a relative path. In the latter
case, the current SKILL path is searched if it’s not nil. Note that a path which is anchored to
current directory, for example, ./, ../, or ../../.., etc., is not considered as a relative
path.
The SKILL path can be overriden by specifying tl_path.
Arguments
S_name Name of the file you want to check.
tl_path List of paths to override the SKILL path.
Value Returned
t The S_name file has a size greater than 2GB.
nil The S_name file has a size less than or equal to 2GB.
Example
fileLength( "largeFile" ) => 3072000000
isLargeFile( "largeFile" ) => t
Reference
fileLength, isDir, isFile, isFileName
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isLink
isLink(
S_name
[ tl_path ]
)
=> t | nil
Description
Checks if a path exists and if it is a symbolic link.
When S_name is a relative path, the current SKILL path is used if it’s non-nil. Note that a
path which is anchored to current directory, for example, ./, ../,or../../.., etc., is not
considered as a relative path.
Arguments
S_name Path you want to check.
tl_path List of paths that override the SKILL path.
Value Returned
t The name exists and it is a symbolic link.
nil The name exists and is not a symbolic name or if S_name does
not exist at all.
Example
isLink("/usr/bin")=> nil
isLink("/usr/spool")=> t ;Assuming it’s a link to /var/spool
Reference
isFile, isDir
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isMacro
isMacro(
s_symbolName
)
=> t | nil
Description
Checks if the given symbol denotes a macro.
Arguments
s_symbolName Symbol to check.
Value Returned
t The given symbol denotes a macro.
nil Otherwise.
Example
(isMacro 'plus) => nil
(isMacro 'defmacro) => t
Reference
defmacro
SKILL Language Reference
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August 2005 248 Product Version 06.40
isNaN
isNaN(
f_flownum
)
=> t | nil
Description
Checks if the given flownum argument represents NaN (not-a-number), nil otherwise.
Arguments
f_flownum A floating-point number.
Value Returned
t If f_flownum is NaN.
nil Otherwise.
Example
nan = 0.0 * 2.0 * 1e999
isNan (nan) => t
isNan (123.456) => nil
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August 2005 249 Product Version 06.40
isReadable
isReadable(
S_name
[ tl_path ]
)
=> t | nil
Description
Checks if you have permission to read a file or list a directory. Uses the current SKILL path
for relative paths. Note that a path which is anchored to current directory, for example, ./,
../, or ../../.., etc., is not considered as a relative path.
Arguments
S_name Name of a file or directory you want to know your access
permissions on.
tl_path List of paths to override the SKILL path.
Value Returned
t If S_name exists and you have permission to read it (for files) or
list the contents (for directories).
nil The file does not exist or does exist, but you do not have
permission to read it.
Example
isReadable("./") => t
Result if current working directory is readable.
isReadable("~/DACLib") => nil
Result if "~/DACLib" is not readable or does not exist.
Reference
infile, isExecutable, isFile, isWritable
SKILL Language Reference
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isWritable
isWritable(
S_name
[ tl_path ]
)
=> t | nil
Description
Checks if you have permission to write to a file or update a directory. Uses the current SKILL
path for relative paths. Note that a path which is anchored to current directory, for example,
./, ../, or ../../.., etc., is not considered as a relative path.
Arguments
S_name Name of a file or directory you want to find out your write
permission on.
tl_path List of paths to search that overrides the SKILL path.
Value Returned
t If S_name exists and you have permission to write or update it.
nil The file does not exist or does exist, but you do not have
permission to read it.
Example
isWritable("/tmp")=> t
isWritable("~/test/out.1") => nil
Result if out.1 does not exist or there is no write permission to it.
Reference
isExecutable, isFile, isReadable
SKILL Language Reference
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August 2005 251 Product Version 06.40
lambda
lambda(
( s_formalArgument )
g_expr1 ...
)
=> U_result
Description
Defines a function without a name. This is a syntax form.
The keywords lambda and nlambda allow functions to be defined without having names.
This is useful for writing temporary or local functions. In all other respects lambda is identical
to the procedure form.
Arguments
s_formalArgument Formal argument for the function definition.
g_expr1 SKILL expression to be evaluated when the function is called.
Value Returned
U_result A function object.
Example
(lambda( (x y) x + y ) 5 6)
=> 11
Reference
apply, nlambda - SKILL mode only, nprocedure - SKILL mode only, putd, procedure
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August 2005 252 Product Version 06.40
last
last(
l_arg
)
=> l_result
Description
Returns the last list cell in a list.
Arguments
l_arg List of elements.
Value Returned
l_result Last list cell (not the last element) in l_arg.
Example
last( '(a b c) ) => (c)
z = '(1 2 3)
last(z) => (3)
last( '(a b c (d e f))) => ((d e f))
Reference
car, cdr, list, listp
SKILL Language Reference
SKILL Language Functions
August 2005 253 Product Version 06.40
lconc
lconc(
l_tconc
l_list
)
=> l_result
Description
Uses a tconc structure to efficiently splice a list to the end of another list.
See the example below.
Arguments
l_tconc A tconc structure that must initially be created using the tconc
function.
l_list List to be spliced onto the end of the tconc structure.
Value Returned
l_result Returns l_tconc, which must be a tconc structure, with the
list l_list spliced in at the end.
Example
x = tconc(nil 1) ; x is initialized ((1) 1)
lconc(x '(2 3 4)) ; x is now ((1 2 3 4) 4)
lconc(x nil) ; Nothing is added to x.
lconc(x '(5)) ; x is now ((1 2 3 4 5) 5)
x = car( x ) ; x is now (1 2 3 4 5)
Reference
append, tconc
SKILL Language Reference
SKILL Language Functions
August 2005 254 Product Version 06.40
leftshift
leftshift(
x_val
x_num
)
=> x_result
Description
Returns the integer result of shifting a value a specified number of bits to the left. Prefix form
of the << arithmetic operator. Note that leftshift is logical (that is, vacated bits are 0-
filled).
Arguments
x_val Value to be shifted.
x_num Number of bits x_val is shifted.
Value Returned
x_result Result of the operation.
Example
leftshift(7 2) => 28
leftshift(10 1) => 20
Reference
rightshift
SKILL Language Reference
SKILL Language Functions
August 2005 255 Product Version 06.40
length
length(
lao_arg
)
=> x_result | 0
Description
Determines the length of a list, array, or association table.
Arguments
lao_arg SKILL list, array, or association table.
Value Returned
x_result Length of the lao_arg object. (The length is either the number
of elements in the list or array or the number of key/value pairs in
the association table).
0 lao_arg is nil or an empty array or table.
Example
length( '(a b c d) ) => 4
z = '(1 2 3) => (1 2 3)
length( z ) => 3
declare(a[11])
length( a ) => 11
myTable = makeTable( "atable" 0) => table:atable
myTable[ 'one] = "blue" => "blue"
myTable[ "two"] = '(red) => (r e d)
length(myTable) => 2
Reference
declare, list, makeTable, strlen
SKILL Language Reference
SKILL Language Functions
August 2005 256 Product Version 06.40
leqp
leqp(
n_num1
n_num2
)
=> t | nil
Description
This predicate function checks if the first argument is less than or equal to the second
argument. Prefix form of the <= operator.
Arguments
n_num1 Number to be checked.
n_num2 Number against which n_num1 is checked.
Value Returned
t n_num1 is less than or equal to n_num2.
nil n_num1 is greater than n_num2.
Example
leqp(2 2) => t
leqp(-2 2) => t
leqp(3 2.2) => nil
Reference
geqp, greaterp, lessp
SKILL Language Reference
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August 2005 257 Product Version 06.40
lessp
lessp(
n_num1
n_num2
)
=> t | nil
Description
This predicate function checks if the first argument is less than the second argument. Prefix
form of the < operator.
Arguments
n_num1 Number to be checked.
n_num2 Number against which n_num1 is checked.
Value Returned
t n_num1 is less than n_num2.
nil n_num1 is greater than or equal to n_num2.
Example
lessp(2 2) => nil
lessp(-2 2) => t
lessp(3 2.2) => nil
Reference
geqp, greaterp, leqp
SKILL Language Reference
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August 2005 258 Product Version 06.40
let - SKILL mode
let(
l_bindings
g_expr1 ...
)
=> g_result
Description
Provides a faster alternative to prog for binding local variables only. This is a syntax form.
l_bindings is either a list of variables or a list of the form (s_variable g_value). The
bindings list is followed by one or more forms to be evaluated. The result of the let form is
the value of the last g_expr.
let is preferable to prog in all circumstances where a single exit point is acceptable, and
where the go and label constructs are not required.
Arguments
l_bindings Local variable bindings, can either be bound to a value or nil
(the default).
g_expr1 Any number of expressions.
Value Returned
g_result The result of the last expression evaluated.
Example
x = 5
let( ((x '(a b c)) y)
println( y ) ; Prints nil.
x)
=> (a b c) ; Returns the value of x.
procedure( test( x y )
let( ((x 6) (z "return string"))
if( (equal x y)
then z
else nil)))
SKILL Language Reference
SKILL Language Functions
August 2005 260 Product Version 06.40
let - SKILL++ mode
let(
[ s_var ]
(
(
s_var1
s_initExp1
)
(
s_var2
s_initExp2
) ...
) body
)
=> g_result
Description
Declares a lexical scope in SKILL++ mode. This includes a collection of local variables, as
well as body expressions to be evaluated. This becomes a named let if the optional s_var
is given.
let, letseq and letrec give SKILL++ a block structure. The syntax of the three constructs
is similar, but they differ in the regions they establish for their variable bindings.
■ In a let expression, the initial values are computed before any of the variables become
bound.
■ In a letseq expression, the bindings and evaluations are performed sequentially.
■ In a letrec expression, all the bindings are in effect while their initial values are being
computed, thus allowing mutually recursive definitions.
Use the let form to declare a collection of local variables. You can provide an initialization
expression for each variable. The order of evaluation of the initialization expressions is
unspecified. Each variable has the body of the let expression as its lexical scope. This
means that the initialization expressions should not make cross-references to the other local
variables.
In SKILL++ mode, local defines can appear at the beginning of the body of a let, letseq,
or letrec form.
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August 2005 261 Product Version 06.40
Arguments
s_var When the optional s_var is given, this becomes a named let.
A named let is just like an ordinary let except that s_var is
bound within the body to a function whose formal arguments are
the bound variables and whose body is body.
s_var1 Name of local variable. The variables are bound to fresh
locations holding the result of evaluating the corresponding
initExp.
s_initExp Expression evaluated for the initial value. The initExps are
evaluated in the current environment (in some unspecified
order).
body A sequence of one or more expressions. The expressions in
(body) are evaluated sequentially in the extended environment.
Each local variable binding has body as its scope.
Value Returned
g_result Value of the last expression of body.
Example
let( ( ( x 2 ) ( y 3 ) )
x*y
)
=> 6
let( ( ( x 2 ) ( y 3 ) )
let( (( z 4 ))
x + y + z
) ; let
) ; let
=> 9
let( ( ( x 2 ) ( y 3 ) )
let( (( x 7 ) ( foo lambda( ( z ) x + y + z ) ) )
foo( 5 )
) ; let
) ; let
=> 10 ;not 15
let( ((x 2) (y 3))
define( f(z) x*z+y)
f(5)
SKILL Language Reference
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August 2005 263 Product Version 06.40
letrec - SKILL++ mode
letrec(
(
(
s_var1
s_initExp1
)
(
s_var2
s_initExp2
) ...
)
body)
=> g_result
Description
A letrec expression can be used in SKILL++ mode only. All the bindings are in effect
while their initial values are being computed, thus allowing mutually recursive definitions. Use
letrec to declare recursive local functions.
Recursive let form. Each binding of a variable has the entire letrec expression as its
scope, making it possible to define mutually recursive procedures.
Use letrec when you want to declare recursive local functions. Each initialization
expression can refer to the other local variables being declared, with the following restriction:
each initialization expression must be executable without actually accessing any of those
variables.
For example, a lambda expression satisfies this restriction because its body gets executed
only when called, not when it’s defined.
Arguments
s_var Name of a local variable. The variables are bound to fresh
locations holding undefined values. Each variable is assigned to
the result of the corresponding initExp.
s_initExp1 Expressions evaluated for the initial value. The initExps are
evaluated in the resulting environment (in some unspecified
order).
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body A sequence of one or more expressions. The expressions in
body are evaluated sequentially in the extended environment.
Value Returned
g_result Value of the last expression of body.
Example
letrec(
( ;;; variable list
( f
lambda( ( n )
if( n > 0 then n*f(n-1) else 1
) ; if
) ; lambda
) ; f
) ; variable list
f( 5 )
) ; letrec
=> 120
This example declares a single recursive local function. The local function f computes the
factorial of its argument. The letrec expression returns the factorial of 5.
Reference
begin - SKILL++ mode, define - SKILL++ mode, let - SKILL++ mode, letseq - SKILL++
mode
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August 2005 265 Product Version 06.40
letseq - SKILL++ mode
letseq(
(
(
s_var1
initExp1
)
(
s_var2
initExp2
) ...
)
body)
=> g_result
Description
A letseq expression can be used in SKILL++ mode only. The bindings and evaluations
are performed sequentially.
Use letseq to control the order of evaluation of the initialization expressions. letseq is
similar to let, but the bindings are performed sequentially from left to right, and the scope of
a binding indicated by (var1 initExp1) is that part of the letseq expression to the right
of the binding. Thus the second binding is done in an environment in which the first binding
is visible, and so on.
This form is equivalent to a corresponding sequence of nested let expressions. It is also
equivalent to let* is the standard Scheme syntax. This function is equivalent of let\*() but
it is strongly recommended using this function over let\*().
Arguments
s_var Name of a local variable. Each variable is assigned to the result
of the corresponding initExp.
initExp Expressions evaluated for the initial value. The initExps are
evaluated sequentially in the environments that result from
previous bindings.
body A sequence of one or more expressions.
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Value Returned
g_result Value of the last expression of body.
Example
letseq( ( ( x 1 ) ( y x+1 ) )
y
) ; letseq
=> 2
The code above is a more convenient equivalent to the code below in which you control the
sequence explicitly by the nesting.
let( ( ( x 1 ) )
let( ( ( y x+1 ) )
y
)
)
Reference
begin - SKILL++ mode, define - SKILL++ mode, let - SKILL++ mode, letrec - SKILL++
mode
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lineread
lineread(
[ p_inputPort ]
)
=> t | nil | l_results
Description
Parses the next line in the input port into a list that you can further manipulate.It is used by
the interpreter’s top level to read in all input and understands SKILL and SKILL++ syntax.
Only one line of input is read in unless there are still open parentheses pending at the end of
the first line, or binary infix operators whose right-hand argument has not yet been
supplied, in which case additional input lines are read until all open parentheses have been
closed and all binary infixoperators satisfied. The symbol tis returned if linereadreads
a blank input line and nil is returned at the end of the input file.
Arguments
p_inputPort Input port. The default is piport.
Value Returned
t If the next line read in is blank.
nil If the input port is at the end of file.
l_results Otherwise returns a list of the objects read in from the next
(logical) input line
Example
lineread(piport) ; Reads in the next input expression
f 1 2 + ; First input line of the file being read
3 ; Second input line
=> (f 1 (2 + 3))
lineread(piport)
f(a b c) ; Another input line of the file
=> ((f a b c)) ; Returns a list of input objects
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linereadstring
linereadstring(
t_string
)
=> g_value | nil
Description
Executes lineread on a string and returns the first form read in. Anything after the first form
is ignored.
Arguments
t_string Input string.
Value Returned
g_value The first form (line) read in from the argument string.
nil No form is read (that is, the argument string is all spaces).
Example
linereadstring "abc" => (abc)
linereadstring "f a b c" => (f a b c)
linereadstring "x + y" => ((x + y))
linereadstring "f a b c\n g 1 2 3" => (f a b c)
In the last example, only the first form is read in.
Reference
evalstring, gets, instring, lineread
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list
list(
[ g_arg1
g_arg2 ... ]
)
=> l_result | nil
Description
Creates a list with the given elements.
Arguments
g_arg1 Element to be added to a list.
g_arg2 Additional elements to be added to a list
Value Returned
l_result List whose elements are g_arg1, g_arg2, and so on.
nil No arguments are given.
Example
list(1 2 3) => (1 2 3)
list('a 'b 'c) => (a b c)
Reference
car, cdr, cons, listp, tconc
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listp
listp(
g_value
)
=> t | nil
Description
Checks if an object is a list.
The suffix pis usually added to the name of a function to indicate that it is a predicate function.
Arguments
g_value A data object.
Value Returned
t If g_value is a list, a data type whose internal name is also
list. Note that listp(nil) returns t.
nil Otherwise.
Example
listp('(1 2 3)) => t
listp( nil ) => t
listp( 1 ) => nil
Reference
atom, list, null
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listToVector
listToVector(
l_list
)
=> a_vectorArray
Description
Returns a vector (array) filled with the elements from the given list.
A vector is represented by an array.
Arguments
l_list A list whose elements will be stored in consecutive entries in the
vector.
Value Returned
a_vectorArray Vector filled with the elements from the given list.
Example
V = listToVector( '( 1 2 3 ) ) => array[3]:1954920
V[0] => 1
V[1] => 2
V[2] => 3
V[3]
*Error* arrayref: array index out of bounds - V[3]
Reference
declare, vector, makeVector, vectorToList
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load
load(
t_fileName
[ t_password ]
)
=> t
Description
Opens a file, repeatedly calls lineread to read in the file, immediately evaluating each form
after it is read in. Uses the file extension to determine the language mode (.il for SKILL and
.ils for SKILL++) for processing the language expressions contained in the file. For a
SKILL++ file, the loaded code is always evaluated in the top level environment.
It closes the file when end of file is reached. Unless errors are discovered, the file is read in
quietly. If load is interrupted by pressing Control-c, the function skips the rest of the file
being loaded.
This function uses the file extension to determine the language mode (.il for SKILL and
.ils for SKILL++) for processing the language expressions contained in the file.
SKILL has an autoload feature that allows applications to load functions into SKILL on
demand. If a function being executed is undefined, SKILL checks to see if the name of the
function (a symbol) has a property called autoload attached to it. If the property exists, its
value, which must be either a string or an expression that evaluates to a string, is used as the
name of a file to be loaded. The file should contain a definition for the function that triggered
the autoload. Execution proceeds normally after the function is defined.
Arguments
t_fileName File to be loaded. Uses the file name extension to determine the
language mode to use.
Valid values:
t_password Password, if t_fileName is an encrypted file.
'ils Means the file contains SKILL++ code.
'il Means the file contains SKILL code.
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Value Returned
t The file is successfully loaded.
Example
load( "testfns.il") ; Load file testfns.il
fn.autoload = "myfunc.il" ; Declares an autoload property.
fn(1)
fn is undefined at this point, so this call triggers an autoload of myfunc.il, which contains
the definition of fn. The function call fn(1) is then successfully performed.
fn(2) ; fn is now defined and executes normally.
You might have an application partitioned into two files. Assume that UtilsA.il contains
classic SKILL code and UtilsB.ils contains SKILL/SKILL++ code. The following example
loads both files appropriately.
procedure( trLoadSystem()
load( "UtilsA.il" ) ;;; SKILL code
load( "UtilsB.ils" ) ;;; SKILL++ code
) ; procedure
Reference
include, loadContext, loadi, lineread
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loadi
loadi(
t_fileName
[ t_password ]
)
=> t
Description
Identical to load, except that loadi ignores errors encountered during the load, prints an
error message, and then continues loading.
Opens the named file, repeatedly calls lineread to read in the file, immediately evaluates
each form after it is read in, then closes the file when end of file is reached. Unlike load,
loadi ignores errors encountered during the load. Rather than stopping, loadi causes an
error message to be printed and then continues to end of file. Otherwise, loadi is the same
as load.
Arguments
t_fileName File to be loaded, with the proper extension to specify the
language mode.
t_password Password, if t_fileName is an encrypted file.
Value Returned
t Always returns t.
Example
loadi( "testfns.il" )
Loads the testfns.il file.
loadi( "/tmp/test.il")
Loads the test.il file from the tmp directory.
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August 2005 277 Product Version 06.40
loadstring
loadstring(
t_string
[ s_langMode ]
)
=> t
Description
Opens a string for reading, then parses and executes expressions stored in the string, just as
load does in loading a file.
Note: loadstring is different from evalstring in two ways: (1) it uses lineread mode,
and (2) it always returns t if it evaluates successfully.
Arguments
t_string Input string to be evaluated.
s_langMode Must be a symbol.
Valid values:
Value Returned
t When t_string has been successfully read in and evaluated.
Signals an error if t_string is not a string, or contains ill-
formed SKILL expressions.
Example
loadstring "1+2" => t
loadstring "procedure( f(y) x=x+y )" => t
loadstring "x=10\n f 20\n f 30" => t
x => 60
'ils Means the file contains SKILL++ code.
'il Means the file contains SKILL code.
SKILL Language Reference
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August 2005 279 Product Version 06.40
log
log(
n_number
)
=> f_result
Description
Returns the natural logarithm of a floating-point number or integer.
Arguments
n_number Floating-point number or integer.
Value Returned
f_result Natural logarithm of the value passed in.
If the value of n_number is not a positive number, an error is
signaled.
Example
log( 3.0 ) => 1.098612
Reference
exp, sqrt
SKILL Language Reference
SKILL Language Functions
August 2005 280 Product Version 06.40
log10
log10(
n_number
)
=> f_result
Description
Returns the base 10 logarithm of a floating-point number or integer.
Arguments
n_number Floating-point number or integer.
Value Returned
f_result Base 10 logarithm of the value passed in.
If the value of n_number is not a positive number, an error is
signaled.
Example
log10( 10.0 ) => 1.0
log10(-20.0)
*Error* log10: argument must be positive - -20
Reference
log, sqrt
SKILL Language Reference
SKILL Language Functions
August 2005 281 Product Version 06.40
lowerCase
lowerCase(
S_string
)
=> t_result
Description
Returns a string that is a copy of the given argument with uppercase alphabetic characters
replaced by their lowercase equivalents.
If the parameter is a symbol, the name of the symbol is used.
Arguments
S_string Input string or symbol.
Value Returned
t_result Copy of S_string in lowercase letters.
Example
lowerCase("Hello World!") => "hello world!"
Reference
upperCase
SKILL Language Reference
SKILL Language Functions
August 2005 282 Product Version 06.40
make_<name>
make_<name>(
...
)
=> r_defstruct
Description
Creates an instance of a defstruct specified by <name>.
Arguments
... Initial values for structure elements (slots).
Value Returned
r_defstruct Copy of the given instance
Example
defstruct(myStruct a b c) => t
m1 = make_myStruct(?a 3 ?b 2 ?c 1) => array[5]:3436504
m2 = copy_myStruct(m1) => array[5]:3436168
Reference
copy_<name>, copyDefstructDeep, defstruct, printstruct, defstructp
SKILL Language Reference
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makeTable
makeTable(
S_name
[
g_default_value ]
)
=> o_table
Description
Creates an empty association table.
Arguments
S_name Print name (either a string or symbol) of the new table.
g_default_value Default value to be returned when references are made to keys
that are not in the table. If no default value is given, the system
returns unbound if the key is not defined in the table.
Value Returned
o_table The new association table.
Example
myTable = makeTable("atable1" 0) => table:atable1
myTable[1] => 0
If you specify a default value when you create the table, the default value is returned if a
nonexistent key is accessed.
myTable2 = makeTable("atable2") => table:atable2
myTable2[1] => unbound
If you do not specify a default value when you create the table, the symbol unbound is
returned if an undefined key is accessed.
myTable[1] = "blue" => blue
myTable["two"] = '(r e d) => (r e d)
myTable['three] = 'green => green
You can refer to and set the contents of an association table with the standard syntax for
accessing array elements.
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makeTempFileName
makeTempFileName(
S_nameTemplate
)
=> t_name
Description
Appends a string suffix to the last component of a path template so that the resulting
composite string does not duplicate any existing file name.
That is, it checks that such named file does not exist. SKILL path is not used in this checking.
Note: Successive calls to makeTempFileName return different results only if the first name
returned is actually used to create a file in the same directory before a second call is made.
The last component of the resultant path is guaranteed to be no more than 14 characters. If
the original template has a long last component it is truncated from the end if needed. Also,
any trailing X’s (uppercase only) are removed from the template before the new string suffix
is appended. You are encouraged to follow the convention of placing temporary files in the
/tmp directory on your system.
Arguments
S_nameTemplate Template file name as a string or a symbol.
Value Returned
t_name Path that can be used to create a file or directory.
Example
d = makeTempFileName("/tmp/testXXXX") => "/tmp/testa00324"
Trailing X’s (uppercase only) are removed.
createDir(d) => t
The name is used this time.
makeTempFileName("/tmp/test") => "/tmp/testb00324"
A new name is returned this time.
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makeVector
makeVector(
x_size
[ g_init_val ]
)
=> a_vectorArray
Description
Creates an array (vector) with the specified number of elements, and optionally initializes
each entry.
Allocates a vector of x_size number of entries. makeVector initializes each entry in the
vector with g_init_val. The default value of g_init_val is the symbol unbound.
Arguments
x_size Size of the vector to be allocated.
g_init_val Initial value of each entry of the vector to be allocated.
Value Returned
a_vectorArray Array of the given size.
Example
V = makeVector( 3 0 ) => array[3]:1955240
V[0] => 0
V[1] => 0
V[2] => 0
Reference
listToVector
SKILL Language Reference
SKILL Language Functions
August 2005 287 Product Version 06.40
map
map(
u_func
l_arg1
[ l_arg2 ... ]
)
=> l_arg1
Description
Applies the given function to successive sublists of the argument lists and returns the first
argument list. All of the lists should have the same length. This function is not the same as
the standard Scheme map function. To get the behavior of the standard Scheme map
function, use mapcar instead.
Note: This function is usually used for its side effects, not its return value (see mapc).
Caution
This function is not the same as the standard Scheme map function. To
get the behavior of the standard Scheme map function, use mapcar
instead.
Arguments
u_func Function to apply to successive sublists. Must be a function that
accepts lists as arguments.
l_arg1 Argument list.
l_arg2 Additional argument lists, which must be the same length as
l_arg1.
Value Returned
l_arg1 The first argument list.
Example
map( 'list '(1 2 3) '(9 8 7) )
=> (1 2 3)
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No interesting side effect.
map( '(lambda (x y) (print (append x y))) '(1 2 3) '(9 8 7) )
(1 2 3 9 8 7) (2 3 8 7) (3 7)
=> (1 2 3)
Prints three lists as a side effect and returns the list (1 2 3).
Reference
apply, foreach, mapc, mapcar, mapcan, maplist
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August 2005 289 Product Version 06.40
mapc
mapc(
u_func
l_arg1
[ l_arg2 ... ]
)
=> l_arg1
Description
Applies a function to successive elements of the argument lists and returns the first argument
list. All of the lists should have the same length. mapc returns l_arg1.
mapc is primarily used with a u_func that has side effects, because the values returned by
the u_func are not preserved. u_func must be an object acceptable as the first argument
to apply and it must accept as many arguments as there are lists. It is first passed the car of
all the lists given as arguments. The elements are passed in the order in which the lists are
specified. The second elements are passed to u_func, and so on until the last element.
Arguments
u_func Function to apply to argument lists.
l_arg1 Argument list.
l_arg2 Additional argument lists, which must be the same length as
l_arg1.
Value Returned
l_arg1 The first argument list.
Example
mapc( 'list '(1 2 3) '(9 8 7) ) => (1 2 3)
mapc( '(lambda (x y) (print (list x y))) '(1 2 3) '(9 8 7) )
(1 9) (2 8) (3 7) => (1 2 3)
Prints three lists as a side effect and returns the list (1 2 3).
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mapcan
mapcan(
u_func
l_arg1
[ l_arg2 ... ]
)
=> l_result
Description
Applies a function to successive elements of the argument lists and returns the result of
appending these intermediate results. All of the lists should have the same length.
Specifically, a function is applied to the carof all the argument lists, passed in the same order
as the argument lists. The second elements are processed next, continuing until the last
element is processed. The result of each call to u_func must be a list. These lists are
concatenated using nconc and the resulting list of all the concatenations is the result of
mapcan. The argument u_func must accept as many arguments as there are lists.
Arguments
u_func Function to apply to argument lists.
l_arg1 Argument list.
l_arg2 Additional argument lists, which must be the same length as
l_arg1.
Value Returned
l_result List consisting of the concatenated results.
Example
mapcan( 'list '(1 2 3) '(a b c) )
=> (1 a 2 b 3 c)
mapcan( (lambda (n) (and (plusp n) (list n))) '(1 -2 3 -4 5))
=> (1 3 5)
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mapcar
mapcar(
u_func
l_arg1
[ l_arg2 ... ]
)
=> l_result
Description
Applies a function to successive elements of the argument lists and returns the list of the
corresponding results. All of the lists should have the same length.
The values returned from successive calls to u_func are put into a list using the list
function.
Arguments
u_func Function to be applied to argument lists. The result of each call
to u_func can be of any data type.
l_arg1 Argument list.
l_arg2 Additional argument lists, which must be the same length as
l_arg1.
Value Returned
l_result A list of results from applying u_func to successive elements of
the argument list.
Example
mapcar( 'plus '(1 2 3) '(9 8 7) )
=> (10 10 10)
mapcar( 'list '(a b c) '(1 2 3) '(x y z) )
=> ((a 1 x) (b 2 y) (c 3 z))
mapcar( 'lambda( (x) plus( x 1 )) '(2 4 6) )
=> (3 5 7)
SKILL Language Reference
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August 2005 295 Product Version 06.40
maplist
maplist(
u_func
l_arg1
[ l_arg2 ... ]
)
=> l_result
Description
Applies a function to successive sublists of the argument lists and returns a list of the
corresponding results. All of the lists should have the same length.
The returned values of the successive function calls are concatenated using the function
list.
Arguments
u_func Function to be applied to argument lists. Must accept lists as
arguments. The result of calling u_func can be of any data
type.
l_arg1 Argument list.
l_arg2 Additional argument lists, which must be the same length as
l_arg1.
Value Returned
l_result A list of the results returned from calling u_func on successive
sublists of the argument list.
Example
maplist( 'length '(1 2 3) )
=> (3 2 1)
maplist( 'list '(a b c) '(1 2 3) )
=> (((a b c)(1 2 3))((b c)(2 3))((c)(3)))
SKILL Language Reference
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August 2005 297 Product Version 06.40
max
max(
n_num1
n_num2
[ n_num3 ... ]
)
=> n_result
Description
Returns the maximum of the values passed in. Requires a minimum of two arguments.
Arguments
n_num1 First value to check.
n_num2 Next value to check.
n_num3 Additional values to check.
Value Returned
n_result Maximum of the values passed in.
Example
max(3 2 1) => 3
max(-3 -2 -1) => -1
Reference
abs, min, numberp
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August 2005 298 Product Version 06.40
measureTime
measureTime(
g_expression ...
)
=> l_result
Description
Measures the time needed to evaluate an expression and returns a list of four numbers. This
is a syntax form.
■ The first number is the amount of user CPU time in seconds devoted to the process.
■ The second number is the amount of CPU time used by the kernel for the process.
■ The third and most significant number is the total elapsed time it took to evaluate the
expression in seconds.
■ The fourth number is the number of page faults that occurred during the evaluation of the
expression.
Arguments
g_expression Expression(s) to be evaluated and timed.
Value Returned
l_result Returns the elapsed time and number of page faults to evaluate
g_expression.
Example
myList = nil ; Initializes the variable myList.
measureTime( for( i 1 10000 myList = cons(i myList) ) )
=> (0.4 0.05 0.4465 0)
Result indicates that it took .4 seconds and 0 page faults to build a list from 1 to 10,000 using
cons.
myList = nil ; Initializes the variable myList.
measureTime( for( i 1 1000 myList = append1(myList i) ) )
=> (5.04 0.03 5.06 0)
SKILL Language Reference
SKILL Language Functions
August 2005 300 Product Version 06.40
member, memq, memv
member(
g_obj
l_list
)
=> l_sublist | nil
Description
Returns the largest sublist of l_list whose first element is g_obj. For comparison,
member uses the equal function, memq uses the eq function, and memv uses eqv.
memqshould only be used when comparing symbols and lists. See eqfor restrictions on when
eq based comparisons can be used.
Note: It is faster to convert a string to a symbol using concat in conjunction with memq than
to simply use member, which performs a comparison using equal which is slower, especially
for large lists. These functions return a non-nil value if the first argument matches a member
of the list passed in as the second argument.
Arguments
g_obj Element to be searched for in l_list.
l_list List to search.
Value Returned
l_sublist The part of l_list beginning with the first match of g_obj.
nil If g_obj is not in the top level of l_list.
Example
x = "c" => "c"
member( x '("a" "b" "c" "d")) => ("c" "d")
memq('c '(a b c d c d)) => (c d c d)
memq( concat( x ) '(a b c d )) => (c d)
memv( 1.5 '(a 1.0 1.5 "1.5")) => (1.5 "1.5")
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min
min(
n_num1
n_num2
[ n_num3 ... ]
)
=> n_result
Description
Returns the minimum of the value passed in. Requires a minimum of two arguments.
Arguments
n_num1 First value to check.
n_num2 Next value to check.
n_num3 Additional values to check.
Value Returned
n_result Minimum of the values passed in.
Example
min(1 2 3) => 1
min(-1 -2.0 -3) => -3.0
Reference
abs, max, numberp
SKILL Language Reference
SKILL Language Functions
August 2005 303 Product Version 06.40
minus
minus(
n_op
)
=> n_result
Description
Returns the negative of a number. Prefix form of the - unary operator.
Arguments
n_op A number.
Value Returned
n_result Negative of the number.
Example
minus( 10 ) => -10
minus( -1.0 ) => 1.0
minus( -0 ) => 0
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August 2005 304 Product Version 06.40
minusp
minusp(
n_num
)
=> t | nil
Description
Checks if a value is a negative number. Same as negativep.
Arguments
n_num Number to check.
Value Returned
t If n_num is a negative number.
nil Otherwise.
Example
minusp( 3 ) => nil
minusp( -3 ) => t
Reference
evenp, negativep, numberp, oddp, onep, plusp, zerop
SKILL Language Reference
SKILL Language Functions
August 2005 305 Product Version 06.40
mod
mod(
x_integer1
x_integer2
)
=> x_result
Description
Returns the integer remainder of dividing two integers. The remainder is either zero or has
the sign of the dividend.
This function is equivalent to remainder.
Arguments
x_integer1 Dividend.
x_integer2 Divisor.
Value Returned
x_result Integer remainder of the division. The sign is determined by the
dividend.
Example
mod(4 3) => 1
Reference
fixp, modulo, remainder
SKILL Language Reference
SKILL Language Functions
August 2005 306 Product Version 06.40
modf
modf(
f_flonum1
f_flonum2
)
=> f_result
Description
Returns the floating-point remainder of the division of f_flonum1 by f_flonum2.
Arguments
Value Returned
f_result Floating-point remainder of the division.
The sign is determined by the dividend.
Example
;; Sign is determined by the dividend
modf(-10.1 10.0) => -0.1
modf(10.1 -10.0) => 0.1
f_flonum1 A floating-point number (Dividend).
f_flonum2 A floating-point number (Divisor).
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August 2005 307 Product Version 06.40
modulo
modulo(
x_integer1
x_integer2
)
=> x_integer
Description
Returns the remainder of dividing two integers. The remainder always has the sign of the
divisor.
The remainder (mod) and modulo functions differ on negative arguments. The remainder
is either zero or has the sign of the dividend if you use the remainder function. With modulo
the return value always has the sign of the divisor.
Arguments
x_integer1 Dividend.
x_integer2 Divisor.
Value Returned
x_integer The remainder of the division. The sign is determined by the
divisor.
Example
modulo( 13 4) => 1
remainder( 13 4) => 1
modulo( -13 4) => 3
remainder( -13 4) => -1
modulo( 13 -4) => -3
remainder( 13 -4) => 1
modulo( -13 -4) => -1
remainder( -13 -4) => -1
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August 2005 309 Product Version 06.40
mprocedure
mprocedure(
s_macroName(
s_formalArgument
)
g_expr1 ...
)
=> s_funcName
Description
Defines a macro with the given name that takes a single formal argument. This is a syntax
form.
The body of the macro is a list of expressions to be evaluated one after another. The value of
the last expression evaluated is considered the result of macro expansion and is evaluated
again to get the actual value of the macro call.
When a macro is called, s_formalArgument is bound to the entire macro call form, that
is, a list with the name of the macro as its first element followed by the unevaluated arguments
to the macro call.
Macros in SKILL are completely general in that a macro body can call any other function to
build an expression that is to be evaluated again.
Note: A macro call within a function definition is expanded only once, when the function is
compiled. For this reason, be cautious when defining macros. Make sure they are purely
functional, that is, side-effects free. You can use expandMacro to verify the correct behavior
of a macro definition.
Arguments
s_macroName Name of the macro function.
s_formalArgument Formal arguments for the macro definition.
g_expr1 A SKILL expression.
Value Returned
s_funcName Name of the macro defined.
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nconc
nconc(
l_arg1
l_arg2
[ l_arg3 ... ]
)
=> l_result
Description
Equivalent to a destructive append where the first argument is actually modified.
This results in nconc being much faster than append but not quite as fast as tconc and
lconc. Thus nconc returns a list consisting of the elements of l_arg1, followed by the
elements of l_arg2, followed by the elements of l_arg3, and so on. The cdr of the last
list cell of l_arg
i
is modified to point to l_arg
i+1
. Thus caution must be taken because if
nconc is called with the l_arg
i
two consecutive times it can form an infinite structure where
the cdr of the last list cell of l_arg
i
points to the car of l_arg
i
.
Use the nconc function principally to reduce the amount of memory consumed. A call to
append would normally duplicate the first argument whereas nconc does not duplicate any
of its arguments, thereby reducing memory consumption.
Arguments
l_arg1 List of elements.
l_arg2 List elements concatenated to l_arg1.
l_arg3 Additional lists.
Value Returned
l_result The modified value of l_arg1.
Example
x = '(a b c)
nconc( x '(d)) ; x is now (a b c d)
nconc( x '(e f g) ) ; x is now the list (a b c d e f g)
nconc( x x ) ; Forms an infinite structure.
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ncons
ncons(
g_element
)
=> l_result
Description
Builds a list containing an element. Equivalent to cons( g_element nil ).
Arguments
g_element Element to be added to the beginning of an empty list.
Value Returned
l_result A list with g_element as its single element.
Example
ncons( 'a ) => (a)
z = '(1 2 3) => (1 2 3)
ncons( z ) => ((1 2 3))
Reference
cons, list
SKILL Language Reference
SKILL Language Functions
August 2005 314 Product Version 06.40
needNCells
needNCells(
{s_cellType | S_userType}
x_cellCount
)
=> t | nil
Description
Ensures that there is enough memory available for the specified number of SKILL objects
(cells).
If necessary, more memory is allocated. The name of the user type can be passed in as a
string or a symbol, however internal types like list or fixnum must be passed in as
symbols.
Arguments
s_cellType Objects of type cellType.
S_userType Objects of type userType.
x_cellCount Number of objects.
Value Returned
t Enough memory is available.
nil Otherwise.
Example
needNCells( 'list 1000 ) => t
Guarantees there will always be 1000 list cells available in the system.
Reference
gc, summary
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August 2005 315 Product Version 06.40
negativep
negativep(
n_num
)
=> t | nil
Description
Checks if a value is a negative number. Same as minusp.
Arguments
n_num Number to check.
Value Returned
t n_num is a negative number.
nil Otherwise.
Example
negativep( 3 ) => nil
negativep( -3 ) => t
Reference
evenp, minusp, numberp, oddp, onep, plusp, zerop
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SKILL Language Functions
August 2005 316 Product Version 06.40
neq
neq(
g_arg1
g_arg2
)
=> t | nil
Description
Checks if two arguments are not identical using the eq function and returns t if they are not.
That is, g_arg1 and g_arg2 are tested to see if they are at the same address in memory.
Arguments
g_arg1 Any SKILL object.
g_arg2 Any SKILL object.
Value Returned
t If g_arg1 and g_arg2 are not eq.
nil Otherwise.
Example
a = 'dog => dog
neq( a 'dog ) => nil
neq( a 'cat ) => t
z = '(1 2 3) => (1 2 3)
neq(z z) => nil
neq('(1 2 3) z) => t
Reference
eq, equal, nequal
SKILL Language Reference
SKILL Language Functions
August 2005 317 Product Version 06.40
nequal
nequal(
g_arg1
g_arg2
)
=> t | nil
Description
Checks if two arguments are not logically equivalent using the equal function and returns t
if they are not.
g_arg1 and g_arg2 are only equal if they are either eqv or they are both lists/strings and
their contents are the same.
Arguments
g_arg1 Any SKILL object.
g_arg2 Any SKILL object.
Value Returned
t If g_arg1 and g_arg2 are not equal.
nil Otherwise.
Example
x = "cow" => "cow"
nequal( x "cow" ) => nil
nequal( x "dog" ) => t
z = '(1 2 3) => (1 2 3)
nequal(z z) => nil
nequal('(1 2 3) z) => nil
Reference
neq, equal
SKILL Language Reference
SKILL Language Functions
August 2005 318 Product Version 06.40
newline
newline(
[ p_outputPort ]
)
=> nil
Description
Prints a newline (\n) character and then flushes the output port.
Arguments
p_outputPort Output port. Defaults to poport, the standard output port.
Value Returned
nil Prints a newline and then returns nil.
Example
print("Hello") newline() print("World!")
"Hello"
"World!"
=> nil
Reference
drain, fprintf, outfile
SKILL Language Reference
SKILL Language Functions
August 2005 319 Product Version 06.40
nindex
nindex(
t_string1
S_string2 )
=> x_result | nil
Description
Finds the symbol or string, S_string2, in t_string1 and returns the character index,
starting from one, of the first point at which the S_string2 matches part of t_string1.
Arguments
t_string1 String you want to search for S_string2.
S_string2 String you want to find occurrences of in t_string1.
Value Returned
x_result Index corresponding to the point at which S_string2 matches
part of t_string1. The index starts from one.
nil No character match.
Example
nindex( "abc" 'b ) => 2
nindex( "abcdabce" "dab" ) => 4
nindex( "abc" "cba" ) => nil
Reference
getchar, index, substring
SKILL Language Reference
SKILL Language Functions
August 2005 320 Product Version 06.40
nlambda - SKILL mode only
nlambda(
(
s_formalArgument
)
g_expr1 ...
)
=> u_result
Description
Allows nlambda functions to be defined without having names. In all other respects,
nlambda is identical to nprocedure. This is a syntax form that is not supported in SKILL++
mode.
Allowing nlambda functions to be defined without having names is useful for writing
temporary or local functions. In all other respects nlambda is identical to nprocedure.
An nlambda function should be declared to have a single formal argument. When evaluating
an nlambda function, SKILL collects all the actual argument expressions unevaluated into a
list and binds that list to the single formal argument. The body of the nlambda can selectively
evaluate the elements of the argument list.
In general, it is preferable to use lambda instead of nlambda because lambda is more
efficient. In most cases, nlambdas can be easily replaced by macros (and perhaps helper
functions).
Arguments
s_formalArgument Formal argument for the function definition.
g_expr1 SKILL expressions to be evaluated when the function is called.
Value Returned
u_result A function object.
Example
putd( 'foo nlambda( (x) println( x )))=> funobj:0x309128
SKILL Language Reference
SKILL Language Functions
August 2005 322 Product Version 06.40
not
not(
g_obj
)
=> t | nil
Description
Same as the ! operator. Returns t if the object is nil, and returns nil otherwise.
Arguments
g_obj Any SKILL object.
Value Returned
t If g_obj is nil.
nil Otherwise.
Example
(not nil) => t
(not 123) => nil
(not t) => nil
Reference
null
SKILL Language Reference
SKILL Language Functions
August 2005 323 Product Version 06.40
nprocedure - SKILL mode only
nprocedure(
s_funcName(
s_formalArgument
)
g_expr1 ...
)
=> s_funcName
Description
Defines an nlambda function with a function name and a single formal argument. This is a
syntax form that is not supported in SKILL++ mode.
The body of the procedure is a list of expressions to be evaluated one after another. The value
of the last expression evaluated is returned as the value of the function. There must be no
white space separating the s_funcName and the open parenthesis of the list containing
s_formalArgument.
An nlambda function defined by nprocedure differs from a lambda function defined by
procedure in that an nlambda function does not evaluate its arguments; it binds the whole
actual argument list to its single formal argument. lambda functions, on the other hand,
evaluate each argument in the actual argument list and bind them one by one to each formal
argument on the formal argument list. It is recommended that procedure be used over
nprocedurewhenever possible, in part because procedure is faster and also offers better
type checking.
In general, it is preferable to use lambda instead of nlambda because lambda is more
efficient.
Arguments
s_funcName Name of newly defined function.
s_formalArgument Formal argument for the function definition.
g_expr1 SKILL expressions to be evaluated when the function is called.
Value Returned
s_funcName Returns the name of the function defined.
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August 2005 324 Product Version 06.40
Example
procedure( printarg(x) println(x))
=> printarg
Defines a lambda function.
nprocedure( nprintarg(x) println(x))
=> nprintarg
Defines an nlambda function.
y = 10
=> 10
printarg(y * 2)
20
=> nil
Calls a lambda function. Prints the value 20. println returns nil.
nprintarg(y * 2)
((y * 2))
=> nil
Calls an nlambda function. Prints a list of the unevaluated arguments. println returns nil.
Reference
lambda, nlambda - SKILL mode only, procedure
SKILL Language Reference
SKILL Language Functions
August 2005 325 Product Version 06.40
nth
nth(
x_index0
l_list
)
=> g_result | nil
Description
Returns an index-selected element of a list, assuming a zero-based index.
Thus nth(0 l_list) is the same as car(l_list). The value nil is returned if
x_index0 is negative or is greater than or equal to the length of the list.
Arguments
x_index0 Index of the list element you want returned.
l_list List of elements.
Value Returned
g_result Indexed element of l_list, assuming a zero-based index
nil If x_index0 is negative or is greater than or equal to the length
of the list.
Example
nth( 1 '(a b c) ) => b
z = '(1 2 3) => (1 2 3)
nth(2 z) => 3
nth(3 z) => nil
Reference
car, list, nthcdr, nthelem
SKILL Language Reference
SKILL Language Functions
August 2005 326 Product Version 06.40
nthcdr
nthcdr(
x_count
l_list
)
=> l_result
Description
Applies cdr to a list a given number of times.
Arguments
x_count Number of times to apply cdr to l_list.
l_list List of elements.
Value Returned
l_result Result of applying cdr to l_list, x_count number of times.
Example
nthcdr( 3 '(a b c d)) => (d)
z = '(1 2 3)
nthcdr(2 z) => (3)
nthcdr(-1 z) => (nil 1 2 3)
If x_count is less than 0, then cons(nil l_list) is returned.
Reference
cdr, cons, nth
SKILL Language Reference
SKILL Language Functions
August 2005 327 Product Version 06.40
nthelem
nthelem(
x_index1
l_list
)
=> g_result | nil
Description
Returns the indexed element of the list, assuming a one-based index.
Thus nthelem(1 l_list) is the same as car(l_list).
Arguments
x_index1 Index of the element of l_list you want returned.
l_list List of elements.
Value Returned
g_result The x_index1 element of l_list.
nil If x_index1 is less than or equal to 0 or is greater than the
length of the list.
Example
nthelem( 1 '(a b c) ) => a
z = '(1 2 3)
nthelem(2 z) => 2
Reference
car, nth
SKILL Language Reference
SKILL Language Functions
August 2005 328 Product Version 06.40
null
null(
g_value
)
=> t | nil
Description
Checks if an object is equal to nil.
null is a type predicate function.
Arguments
g_value A data object.
Value Returned
t If g_value is equal to nil.
nil Otherwise.
Example
null( 3 ) => nil
null('()) => t
null( nil) => t
Reference
atom, listp
SKILL Language Reference
SKILL Language Functions
August 2005 329 Product Version 06.40
numberp
numberp(
g_value
)
=> t | nil
Description
Checks if a data object is a number, that is, either an integer or floating-point number.
The suffix pis usually added to the name of a function to indicate that it is a predicate function.
Arguments
g_value A data object.
Value Returned
t The data object is a number.
nil Otherwise.
Example
numberp( 3 ) => t
numberp('isASymbol) => nil
numberp( 3.5) => t
Reference
fixp, floatp
SKILL Language Reference
SKILL Language Functions
August 2005 330 Product Version 06.40
numOpenFiles
numOpenFiles(
)
=> ( x_current x_maximum )
Description
Returns the number of files now open and the maximum number of files that a process can
open. The numbers are returned as a two-element list.
Arguments
None.
Value Returned
x_current Number of files that are currently open.
x_maximum Maximum number of files that a process can open. This is
usually platform-dependent.
Example
numOpenFiles() => (6 64)
Result is system-dependent.
f = infile("/dev/null") => port:"/dev/null"
numOpenFiles() => (7 64)
One more file is open now.
Reference
close, infile, outfile
SKILL Language Reference
SKILL Language Functions
August 2005 331 Product Version 06.40
oddp
oddp(
x_num
)
=> t | nil
Description
Checks if the value of an integer is odd.
oddp is a predicate function.
Arguments
x_num An integer.
Value Returned
t If x_num is an odd integer.
nil Otherwise.
Example
oddp( 7 )
=> t
oddp( 8 )
=> nil
Reference
evenp, fixp, integerp, minusp, onep, plusp, zerop
SKILL Language Reference
SKILL Language Functions
August 2005 332 Product Version 06.40
onep
onep(
n_num
)
=> t | nil
Description
Checks if a value is equal to one.
onep is a predicate function.
Arguments
n_num Number to check.
Value Returned
t If n_num is equal to one.
nil Otherwise.
Example
onep( 1 )
=> t
onep( 7 )
=> nil
onep( 1.0 )
=> t
Reference
evenp, minusp, numberp, oddp, plusp, zerop
SKILL Language Reference
SKILL Language Functions
August 2005 333 Product Version 06.40
openportp
openportp(
g_obj
)
=> t | nil
Description
Checks if the given argument is a port object and it is open (for input or output), nil
otherwise.
Arguments
g_obj Any SKILL object.
Value Returned
t If g_obj is a port and it is open for input or output.
nil Otherwise.
Example
(portp ip = (infile “inFile”)) => t
(portp op = (outfile “outFile”)) => t
(openportp ip) => t
(openportp op) => t
(close ip) => t
(openportp ip) => nil
(close op) => t
(openportp op) => nil
SKILL Language Reference
SKILL Language Functions
August 2005 334 Product Version 06.40
or
or(
g_arg1
g_arg2
[ g_arg3... ]
)
=> nil | g_val
Description
Evaluates from left to right its arguments to see if the result is non-nil. As soon as an
argument evaluates to non-nil, or returns that value without evaluating the rest of the
arguments. If all arguments except the last evaluate to nil, or returns the value of the last
argument as the result of the function call. Prefix form of the || binary operator.
Arguments
g_arg1 First argument to be evaluated.
g_arg2 Second argument to be evaluated.
g_arg3 Optional additional arguments to be evaluated.
Value Returned
nil All arguments evaluate to nil.
g_val Value of the argument that evaluates to non-nil, or the value of
the last argument if all the preceding arguments evaluate to nil.
Example
or(t nil) => t
or(nil t) => t
or(18 12) => 18
Reference
and, band, bnand, bnor, bnot, bor, bxnor, bxor, not
SKILL Language Reference
SKILL Language Functions
August 2005 335 Product Version 06.40
otherp
otherp(
g_value
)
=> t | nil
Description
Checks if an object is a user type object, such as an association table or a window.
The suffix pis usually added to the name of a function to indicate that it is a predicate function.
Arguments
g_value A data object.
Value Returned
t If g_value is a user type object.
nil Otherwise.
Example
otherp(3.0) => nil
otherp( makeTable("table1" nil)) => t
Reference
type, typep
SKILL Language Reference
SKILL Language Functions
August 2005 336 Product Version 06.40
outfile
outfile(
S_fileName
[ t_mode ]
[ g_openHiddenFile ]
)
=> p_outport | nil
Description
Opens an output port ready to write to a file.
The file can be specified with either an absolute path or a relative path. If a relative path is
given and the current SKILL path setting is not nil, all directory paths from SKILL path are
checked in order, for that file. Note that a path which is anchored to current directory, for
example, ./, ../, or ../../.., etc., is not considered as a relative path. If found, the
system overwrites the first updatable file in the list. If no updatable file is found, it places a
new file of that name in the first writable directory.
If the optional g_openHiddenFile argument (which is intended to be used on Windows
only) is specified, the system will be forced to open a Windows hidden file. The
g_openHiddenFile must be used for openning existing Windows hidden files only. If the
named Windows hidden file does not exist (including the current SKILL path), outfile will
fail. In addition, the t_mode option must also be specified (to either w or a only) if
g_openHiddenFile is given.
Arguments
S_fileName Name of the file to open or create.
t_mode If the mode string t_mode is specified, the file is opened in the
mode requested. If t_mode is a, an existing file is opened in
append mode. If it is w, a new file is created for writing (any
existing file is overwritten). The default is w.
g_openHiddenFile If specified to non-nil, the named Windows hidden file is forced
to open. This argument must be used for Windows hidden files
only.
SKILL Language Reference
SKILL Language Functions
August 2005 337 Product Version 06.40
Value Returned
p_outport An output port ready to write to the specified file.
nil If the named file cannot be opened for writing or the named
Windows hidden file does not exist (including the current SKILL
path).
An error is signaled if an illegal mode string is supplied.
Example
p = outfile("/tmp/out.il" "w") => port:"/tmp/out.il"
outfile("/bin/ls") => nil
outfile( "aHiddenFile" "w" t)
To force opening a Windows hidden file t_mode must also be specified.
Reference
close, drain, getSkillPath, infile
SKILL Language Reference
SKILL Language Functions
August 2005 338 Product Version 06.40
outportp
outportp(
g_obj
)
=> t | nil
Description
Checks if an object is an output port.
Note: An output port may be closed, so if outportp returns t, that does not guarantee a
successful write to the port.
Arguments
g_obj Any SKILL object.
Value Returned
t The given object is an output port.
nil Otherwise.
Example
(outportp poport) => t
(outportp piport) => nil
(outportp 123) => nil
Reference
inportp
SKILL Language Reference
SKILL Language Functions
August 2005 339 Product Version 06.40
pairp
pairp(
g_obj
)
=> t | nil
Description
Checks if an object is a cons object, that is, a non-empty list.
This function is equivalent to dtpr.
Arguments
g_obj Any SKILL object.
Value Returned
t g_obj is a cons object.
nil g_obj is not a cons object.
Example
(pairp nil) => nil
(pairp 123) => nil
(pairp '(1 2)) => t
Reference
dtpr, listp, null
SKILL Language Reference
SKILL Language Functions
August 2005 340 Product Version 06.40
parseString
parseString(
S_string
[ S_breakCharacters ]
)
=> l_strings
Description
Breaks a string into a list of substrings with break characters.
Returns the contents of S_string broken up into a list of words. If the optional second
argument, S_breakCharacters, is not specified, the white space characters, \t\f\r\n\v,
are used as the default.
A sequence of break characters in S_string is treated as a single break character. By this
rule, two spaces or even a tab followed by a space is the same as a single space. If this rule
were not imposed, successive break characters would cause null strings to be inserted into
the output list.
If S_breakCharacters is a null string, S_string is broken up into characters. You can
think of this as inserting a null break character after each character in S_string.
No special significance is given to punctuation characters, so the “words” returned by
parseString might not be grammatically correct.
Arguments
S_string String to be parsed.
S_breakCharacters List of individual break characters.
Value Returned
l_strings List of strings parsed from S_string.
Example
parseString( "Now is the time" ) => ("Now" "is" "the" "time")
Space is the default break character
SKILL Language Reference
SKILL Language Functions
August 2005 341 Product Version 06.40
parseString( "prepend" "e" ) => ("pr" "p" "nd" )
e is the break character.
parseString( "feed" "e") => ("f" "d")
A sequence of break characters in S_string is treated as a single break character.
parseString( "~/exp/test.il" "./") => ("~" "exp" "test" "il")
Both . and / are break characters.
parseString( "abc de" "") => ("a" "b" "c" " " "d" "e")
The single space between c and d contributes " " in the return result.
Reference
buildString, linereadstring, strcat, strlen, stringp
SKILL Language Reference
SKILL Language Functions
August 2005 342 Product Version 06.40
plist
plist(
s_symbolName
)
=> l_propertyList | nil
Description
Returns the property list associated with a symbol.
From time to time, it is useful to print out the entire property list attached to a given symbol
and see what properties have been assigned to the symbol.
Arguments
s_symbolName Name of the symbol.
Value Returned
l_propertyList Property list for the named symbol.
nil If there is no property list for the named symbol.
Example
a.x = 10
a.y = 20
println(plist('a))
(y 20 x 10)
=> nil
Prints the property list attached to the symbol a. Returns nil, the result of println. Notice
that a single quote is used in this example. You can think of this as passing in the name of the
symbol rather than its value.
Reference
putprop, setplist
SKILL Language Reference
SKILL Language Functions
August 2005 343 Product Version 06.40
plus
plus(
n_op1
n_op2
[ n_op3 ... ]
)
=> n_result
Description
Returns the result of adding one or more operands to the first operand. Prefix form of the +
arithmetic operator.
Arguments
n_op1 First number to be added.
n_op2 Second number to be added.
n_op3 Optional additional numbers to be added.
Value Returned
n_result Sum of the numbers.
Example
plus(5 4 3 2 1) => 15
plus(-12 -13) => -25
plus(12.2 13.3) => 25.5
Reference
xplus
SKILL Language Reference
SKILL Language Functions
August 2005 344 Product Version 06.40
plusp
plusp(
n_num
)
=> t | nil
Description
Checks if a value is a positive number.
plusp is a predicate function.
Arguments
n_num Floating-point number or integer.
Value Returned
t If n_num is a positive number.
nil Otherwise.
Example
plusp( -209.623472)
=> nil
plusp( 209.623472)
=> t
Reference
evenp, minusp, numberp, oddp, onep, zerop
SKILL Language Reference
SKILL Language Functions
August 2005 345 Product Version 06.40
portp
portp(
g_value
)
=> t | nil
Description
Checks if an object is an input or output port.
The suffix pis usually added to the name of a function to indicate that it is a predicate function.
Arguments
g_value A data object.
Value Returned
t If g_value is an input or output port, whose type name is port.
nil Otherwise.
Example
portp( piport ) => t
portp( 3.0 ) => nil
Reference
infile, outfile
SKILL Language Reference
SKILL Language Functions
August 2005 346 Product Version 06.40
postdecrement
postdecrement(
s_var
)
=> n_result
Description
Takes a variable, decrements its value by one, stores the new value back into the variable,
and returns the original value. Prefix form of s--. The name of the variable must be a symbol
and the value must be a number.
Arguments
s_var Variable representing a number.
Value Returned
n_result Original value of the variable.
Example
s = 2
postdecrement( s ) => 2
s => 1
s = 2.2
postdecrement( s ) => 2.2
s => 1.2
Reference
postincrement, predecrement, preincrement
SKILL Language Reference
SKILL Language Functions
August 2005 347 Product Version 06.40
postincrement
postincrement(
s_var
)
=> n_result
Description
Takes a variable, increments its value by one, stores the new value back into the variable, and
returns the original value. Prefix form of s++. The name of the variable must be a symbol and
the value must be a number.
Arguments
s_var Variable representing a number.
Value Returned
n_result Original value of the variable.
Example
s = 2
postincrement( s ) => 2
s => 3
s = 2.2
postincrement( s ) => 2.2
s => 3.2
Reference
postdecrement, predecrement, preincrement
SKILL Language Reference
SKILL Language Functions
August 2005 348 Product Version 06.40
pprint
pprint(
g_value
[ p_outputPort ]
)
=> nil
Description
Identical to print except that it pretty prints the value whenever possible.
The pprint function is useful, for example, when printing out a long list where print simply
prints the list on one (possibly huge) line but pprint will limit the output on a single line and
produce a multiple line printout if necessary. This makes the output much more readable.
pprint does not work the same as the pp function. pp is an nlambda and only takes a
function name whereas pprint is a lambda and takes an arbitrary SKILL object.
Arguments
g_value Any SKILL value to be printed.
p_outputPort Output port to print to. Default is poport.
Value Returned
nil Prints the argument value (to the given port).
Example
pprint '(1 2 3 4 5 6 7 8 9 0 a b c d e f g h i j k)
(1 2 3 4 5
6 7 8 9 0
a b c d e
f g h i j
k
)
=> nil
Reference
pp, print
SKILL Language Reference
SKILL Language Functions
August 2005 349 Product Version 06.40
predecrement
predecrement(
s_var
)
=> n_result
Description
Takes a variable, decrements its value by one, stores the new value back into the variable,
and returns the new value. Prefix form of --s. The name of the variable must be a symbol
and the value must be a number.
Arguments
s_var Variable representing a number.
Value Returned
n_result Decremented value of the variable.
Example
s = 2
predecrement( s ) => 1
s => 1
s = 2.2
predecrement( s ) => 1.2
s => 1.2
Reference
postdecrement, postincrement, preincrement
SKILL Language Reference
SKILL Language Functions
August 2005 350 Product Version 06.40
preincrement
preincrement(
s_var
)
=> n_result
Description
Takes a variable, increments its value by one, stores the new value back into the variable, and
returns the new value. Prefix form of ++s. The name of the variable must be a symbol and
the value must be a number.
Arguments
s_var Variable representing a number.
Value Returned
n_result Incremented value of the variable.
Example
s = 2
preincrement( s ) => 3
s => 3
s = 2.2
preincrement( s ) => 3.2
s => 3.2
Reference
postdecrement, postincrement, predecrement
SKILL Language Reference
SKILL Language Functions
August 2005 351 Product Version 06.40
prependInstallPath
prependInstallPath(
S_name
)
=> t_string
Description
Prepends the Cadence installation path to a file or directory and returns the resulting path as
a string.
Possibly adds a slash (/) separator if needed. The typical use of this function is to compute
one member of a list passed to setSkillPath.
Arguments
S_name File or directory name to append to the installation path. If a
symbol is given, its print name is used.
Value Returned
t_string String formed by prepending the installation path to the
argument path.
Example
getInstallPath() => ("/usr5/cds/4.2")
Assume this is your install path.
prependInstallPath( "etc/context" ) => "/usr5/cds/4.2/etc/context"
A slash (/) is added.
prependInstallPath( "/bin" ) => "/usr5/cds/4.2/bin"
setSkillPath( list("." prependInstallPath("bin")
prependInstallPath("etc/context")) )
=> nil
getSkillPath()
=> ("." "/usr5/cds/4.2/bin" "/usr5/cds/4.2/etc/context")
Reference
getInstallPath, getSkillPath, setSkillPath
SKILL Language Reference
SKILL Language Functions
August 2005 352 Product Version 06.40
print
print(
g_value
[ p_outputPort ]
)
=> nil
Description
Prints a SKILL object using the default format for the data type of the value.
For example, strings are enclosed in double quotes. Same as println, except no newline
character is printed.
Arguments
g_value Any SKILL object.
p_outputPort Output port to print to. Default is poport.
Value Returned
nil Always returns nil after printing out the object supplied.
Example
print("hello")
"hello"
=> nil
Reference
pprint, println, printlev
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printf
printf(
t_formatString
[ g_arg1 ... ]
)
=> t
Description
Writes formatted output to poport.
The optional arguments following the format string are printed according to their
corresponding format specifications. Refer to the “
Common Output Format Specifications”
table on the fprintf manual page.
printf is identical to fprintf except that it does not take the p_port argument and the
output is written to poport.
Arguments
t_formatString Characters to be printed verbatim, intermixed with format
specifications prefixed by the % sign.
g_arg1 Arguments following the format string are printed according to
their corresponding format specifications.
Value Returned
t Prints the formatted output and returns t.
Example
x = 197.9687 => 197.9687
printf("The test measures %10.2f.\n" x)
Prints the following line to poport and returns t.
The test measures 197.97.
=> t
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printlev
printlev(
g_value
x_level
x_length
[ p_outputPort ]
)
=> nil
Description
Prints a list with a limited number of elements and levels of nesting.
Lists are normally printed in their entirety no matter how many elements they have or how
deeply nested they are. Applications have the option, however, of setting upper limits on the
number of elements and the levels of nesting shown when printing lists. These limits are
sometimes necessary to control the volume of interactive output because the SKILL top-level
automatically prints the results of expression evaluation. Limits can also protect against the
infinite looping on circular lists possibly created by programming mistakes.
Two integer variables, print length and print level (specified by x_length and x_level),
control the maximum number of elements and the levels of nesting that are printed. List
elements beyond the maximum specified by print length are abbreviated as “...” and lists
nested deeper than the maximum level specified by print level are abbreviated as &. Both print
length and print level are initialized to nil (meaning no limits are imposed) by SKILL, but
each application is free to set its own limits.
The printlev function is identical to print except that it takes two additional arguments
specifying the maximum level and length to be used in printing the expression.
Arguments
g_value Any SKILL value.
x_level Specifies the level of nesting that you want to print; lists nested
deeper than the maximum level specified are abbreviated as “&”.
x_length Specifies the length (or maximum number of elements) you want
to print. List elements beyond the maximum specified here are
abbreviated as “...”.
p_outputPort Output port. Default is poport.
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Value Returned
nil Prints the argument value and then returns nil.
Example
List = '(1 2 (3 (4 (5))) 6)
=> '(1 2 (3 (4 (5))) 6)
printlev(List 100 2)
(1 2 ...)
=> nil
printlev(List 3 100)
(1 2 (3 (4 &)) 6)
=> nil
printlev(List 3 3 p) ; Assumes port p exists.
(1 2 (3 (4 &)) ...) ; Prints to port p.
=> nil
Reference
list, print
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println
println(
g_value
[ p_outputPort ]
)
=> nil
Description
Prints a SKILL object using the default format for the data type of the value, then prints a
newline character.
A newline character is automatically printed after printing g_value. println flushes the
output port after printing each newline character.
Arguments
g_value Any SKILL value.
p_outputPort Port to be used for output. The default is poport.
Value Returned
nil Prints the given object and returns nil.
Example
for( i 1 3 println( "hello" )) ;Prints hello three times.
"hello"
"hello"
"hello"
=> t ;for always returns t
Reference
drain, print, newline
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procedure
procedure(
s_funcName(
l_formalArglist
)
g_expr1 ...
)
=> s_funcName
Description
Defines a function using a formal argument list. The body of the procedure is a list of
expressions to evaluate.
The body of the procedure is a list of expressions to be evaluated one after another when
s_funcName is called. There must be no white space between procedure and the open
parenthesis that follows, nor between s_funcName and the open parenthesis of
l_formalArglist. However, for defun there must be white space between
s_funcName and the open parenthesis. This is the only difference between the two
functions. defun has been provided principally so that you can make your code appear more
like other LISP dialects.
Expressions within a function can reference any variable on the formal argument list or any
global variable defined outside the function. If necessary, local variables can be declared
using the let or prog functions.
Arguments
s_funcName Name of the function you are defining.
l_formalArglist Formal argument list.
g_expr1 Expression or expressions to be evaluated when s_funcName
is called.
Value Returned
s_funcName Name of the function being defined.
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ARGUMENT LIST PARAMETERS
Several parameters provide flexibility in procedure argument lists. These parameters are
referred to as @ (“at”) options. The parameters are @rest, @optional, and @key.
@rest Option
The @restoption allows an arbitrary number of arguments to be passed into a function. Let’s
say you need a function that takes any number of arguments and returns a list of them in
reverse order. Using the @rest option simplifies this task.
Note: The name of the parameter following @rest is changeable. The r has been used for
convenience.
procedure( myReverse( @rest r )
reverse( r ))
=> myReverse
myReverse( 'a 'b 'c )
=> (c b a)
@optional Option
The @optional option gives you another way to specify a flexible number of arguments.
With @optional, each argument on the actual argument list is matched up with an argument
on the formal argument list. If you place @optional in the argument list of a procedure
definition, any argument following it is considered optional.
You can provide any optional argument with a default value. Specify the default value using a
default form. The default form is a two-member list. The first member of this list is the optional
argument’s name. The second member is the default value.
The default value is assigned only if no value is assigned when the function is called. If the
procedure does not specify a default value for a given argument, nil is assigned.
The following is an outline of a procedure that builds a box of a certain length and width.
procedure(buildbox(length width @optional (xcoord 0)
(ycoord 0) color)
.
.
)
Both length and width must be specified when this function is called. However, the color
and the coordinates of the box are declared as optional parameters. If only two parameters
are specified, the optional parameters are given their default values. For xcoord and
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ycoord, those values are 0. Since no value is specified for color, color’s default value
is nil.
Examine the following calls to buildbox and their return values:
buildbox(1 2); Builds a box of length 1, width 2
; at the coordinates (0,0) with the default color nil
buildbox(3 4 5.5 10.5); Builds a box of length 3, width 4
; at coordinates (5.5,10.5) with the default color nil
buildbox(3 4 5 5 'red); Builds a box of length 3, width 4
; at coordinates (5,5) with the default color red.
As illustrated in the above examples, @optional relies on order to determine what actual
arguments are assigned to each formal argument. When relying on order is too lengthy or
inconvenient, another “at” sign parameter, @key, provides an alternative.
@key Option
@key and @optional are mutually exclusive; they cannot appear in the same argument list.
The @key option lets you specify the expected arguments in any order.
For example, examine the following function:
procedure(setTerm(@key (deviceType 'unknown)
(baudRate 9600)
keyClick )
.
.
)
If you call setTerm without arguments (that is, setTerm()), deviceType is set to
unknown, baudRate to 9600, and keyClick to nil. Default forms work the same as they do
for @optional. To specify a keyword for an argument (for example, deviceType,
baudRate, and keyClick in the above function), precede the keyword with a question mark
(?).
To set the baudRate to 4800 and the keyClick to ON, the call is:
setTerm(?baudRate 4800 ?keyClick 'ON)
; This sets baudRate and keyClick. Because nothing
; was specified for deviceType, it is set to its default,
; unknown.
setTerm(?keyClick 'ON ?baudRate 4800) ; Does exactly
; the same as above.
In summary, there are two standard forms that procedure argument lists follow:
procedure(functionname([var1 var2 ...]
[@optional opt1 opt2 ...]
[@rest r])
.
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.
)
procedure(functionname([var1 var2 ...]
[@key key1 key2 ...]
[@rest r])
.
.
)
Example
procedure( cube(x) x**3 ) ; Defines a function to compute the
=> cube ; cube of a number using procedure.
cube( 3 ) => 27
defun( cube (x) x**3 ) ; Defines a function to compute the
=> cube ; cube of a number using defun.
The following function computes the factorial of its positive integer argument by recursively
calling itself.
procedure( factorial(x)
if( (x == 0) then 1
else x * factorial(x - 1)))
=> factorial
defun( factorial (x)
if( (x == 0) then 1
else x * factorial( x - 1)))
=> factorial
factorial( 6 )
=> 720
Reference
defun, let - SKILL mode, nprocedure - SKILL mode only, prog
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procedurep
procedurep(
g_obj
)
=> t | nil
Description
Checks if an object is a procedure, or function, object.
A procedure may be a function object defined in SKILL or SKILL++, or system primitives. Note
that symbols are not considered procedures even though they may have function bindings.
Arguments
g_obj Any SKILL object.
Value Returned
t The argument is a procedure, or function, object.
nil Otherwise.
Example
(procedurep 123 ) => nil
(procedurep (getd 'plus)) => t
(procedurep 'plus) => nil
Reference
defun, isCallable, lambda, procedure
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prog
prog(
l_localVariables
[
[ s_label ]
g_expr1
] ...
)
=> g_result | nil
Description
Allows for local variable bindings and permits abrupt exits on control jumps. This is a syntax
form.
The first argument to prog is a list of variables declared to be local within the context of the
prog. The expressions following the prog are executed sequentially unless one of the
control transfer statements such as go or return is encountered. A prog evaluates to the
value of nil if no return statement is executed and control simply “falls through” the prog
after the last expression is executed. If a return is executed within a prog, the prog
immediately returns with the value of the argument given to the return statement.
Any statement in a prog can be preceded by a symbol that serves as a label for the
statement. Unless multiple return points are necessary or you are using the go function, a
faster construct for binding local variables, let, should be used over prog.
Arguments
l_localVariables List of variables local to prog.
s_label Labels a statement inside a prog; labels can be defined only for
statements at the top level. Statements nested inside another
statement cannot be labelled unless the surrounding statement
is itself a prog.
g_expr1 Any SKILL expression to be evaluated inside the prog.
Value Returned
g_result Value of the return statement if one is used.
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nil Otherwise always returns nil.
Example
x = "hello"
=> "hello"
prog( (x y) ; Declares local variables x and y.
x = 5 ; Initialize x to 5.
y = 10 ; Initialize y to 10.
return( x + y )
)
=> 15
x
=> "hello" ; The global x keeps its original value.
Reference
let - SKILL mode, go, procedure, progn
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prog1
prog1(
g_expr1
[ g_expr2 ... ]
)
=> g_result
Description
Evaluates expressions from left to right and returns the value of the first expression. This is
a syntax form.
Arguments
g_expr1 Any SKILL expression.
g_expr2 Any SKILL expression.
Value Returned
g_result Value of the first expression, g_expr1.
Example
prog1(
x = 5
y = 7 )
=> 5
Returns the value of the first expression.
Reference
prog, prog2, progn
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prog2
prog2(
g_expr1
g_expr2
[ g_expr3... ]
)
=> g_result
Description
Evaluates expressions from left to right and returns the value of the second expression. This
is a syntax form.
Arguments
g_expr1 First SKILL expression.
g_expr2 Second SKILL expression.
g_expr3 Additional SKILL expressions.
Value Returned
g_result Value of the second expression, g_expr2.
Example
prog2(
x = 4
p = 12
x = 6 )
=> 12
Returns the value of the second expression.
Reference
prog, prog1, progn
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progn
progn(
g_expr1 ...
)
=> g_result
Description
Evaluates expressions from left to right and returns the value of the last expression. This is a
syntax form.
progn is useful for grouping a sequence of expressions into a single expression. As a
shorthand notation for progn, use braces ({ }) to group multiple expressions into a single
expression.
Arguments
g_expr1 Any SKILL expression.
Value Returned
g_result Value of the last expression evaluated.
Example
progn(
println("expr 1")
println("expr 2") )
"expr 1"
"expr 2"
=> nil
The value of println is nil. The following example uses braces.
{ println("expr 1")
println("expr 2")
2 + 3}
"expr 1"
"expr 2"
5
Reference
begin - SKILL mode, let - SKILL mode, prog, prog1, prog2
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putd
putd(
s_functionName
u_functionDef
)
=> u_functionDef
Description
Assigns a new function binding, which must be a function, a lambda expression, or nil,to
a function name. If you just want to define a function, use procedure or defun.
Assigns the function definition of u_functionDef to s_functionName. This is different
from alias, which does a macro expansion when evaluated. You can undefine a function
name by setting its function binding to nil. A function name can be write-protected by the
system to protect you from unintentional name collisions, in which case you cannot change
the function binding of that function name using putd.
Note: If you just want to define a function, use procedure or defun.
Arguments
s_functionName Name of the function.
u_functionDef New function binding, which must be a binary function, a
lambda expression, or nil.
Value Returned
u_functionDef Function definition, which is either a binary function or a SKILL
expression.
Example
putd( 'mySqrt getd( 'sqrt ))
=> lambda:sqrt
Assigns the function mySqrt the same definition as sqrt.
putd( 'newFn 'lambda( () println( "This is a new function" )))
=> funobj:0x3cf088
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putprop
putprop(
sl_id
g_value
S_name
)
=> g_value
Description
Adds properties to symbols or disembodied property lists.
If the property already exists, the old value is replaced with a new one. The putprop function
is a lambda function, which means all of its arguments are evaluated.
Arguments
sl_id Symbol or disembodied property list.
g_value Value of the named property.
S_name Name of the property.
Value Returned
g_value The value of the named property.
Example
putprop('s 1+2 'x) => 3
Sets the property x on symbol s to 3.
Reference
get, putpropq, putpropqq
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putpropq
putpropq(
sl_id
g_value
S_name
)
=> g_value
outpropq(
sl_id->s_name = g_value
)
=> g_value
Description
Adds properties to symbols or disembodied property lists. Identical to putprop except that
s_name is not evaluated. If the property already exists, the old value is replaced with a new
one.
Arguments
sl_id Symbol or disembodied property list.
g_value Value of the named property.
S_name Name of the property.
Value Returned
g_value Value of the named property.
Example
putpropq('s 1+2 x) => 3
y = 'x => x
y->x = 1+2 => 3
Both examples are equivalent expressions that set the property x on symbol s to 3.
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putpropqq
putpropqq(
s_id
g_value
S_name
)
=> g_value
outpropqq(
s_id.s_name = g_value
)
=> g_value
Description
Adds properties to symbols. Identical to putprop except that sl_id and s_name are not
evaluated. If the property already exists, the old value is replaced with a new one.
Arguments
s_id Can only be a symbol.
g_value Value of the named property.
S_name Name of the property.
Value Returned
g_value Value of the named property.
Example
putpropqq(s 1+2 x) => 3
s.x = 1+2 => 3
Both examples are equivalent expressions that set the property x on symbol s to 3.
Reference
get, putprop, putpropq
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quote
quote(
g_expr
)
=> g_result
Description
Returns the name of the variable or the expression. Prefix form of the ' operator. Quoting is
used to prevent expressions from being evaluated.
Arguments
g_expr Variable or expression.
Value Returned
g_result Name of the variable or expression.
Example
(quote a) => a
(quote (f a b)) => (f a b)
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quotient
quotient(
n_op1
n_op2
[ n_op3 ... ]
)
=> n_result
Description
Returns the result of dividing the first operand by one or more operands. Prefix form of the /
arithmetic operator.
Arguments
n_op1 Dividend.
n_op2 Divisor.
n_op3 Optional additional divisors for multiple divisions.
Value Returned
n_result Result of the operation.
Example
quotient(5 4 3 2 1) => 0
quotient(-10 -2) => 5
quotient(10.8 -2.2) => -4.909091
Reference
xquotient
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random
random(
[ x_number ]
)
=> x_result
Description
Returns a random integer between zero and a given number minus one.
If you call random with no arguments, it returns an integer that has all of its bits randomly set.
Arguments
x_number An integer.
Value Returned
x_result Random integer between zero and x_number minus one.
Example
random( 93 )
=> 26
Reference
srandom
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range
range(
n_num1
n_num2
)
=> l_result
Description
Returns a list whose first element is n_num1 and whose tail is n_num2. Prefix form of the :
operator.
Arguments
n_num1 First element of the list.
n_num2 Tail of the list.
Value Returned
l_result Result of the operation.
Example
L = range(1 2) => (1 2)
car(L) => 1
cdr(L) => (2)
L = range(1.1 3.3) => (1.1 3.3)
car(L) => 1.1
cdr(L) => (3.3)
Reference
cdr
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read
read(
[ p_inputPort ]
)
=> g_result | nil | t
Description
Parses and returns the next expression from an input port.
Returns the next expression regardless of how many lines the expression takes up - even if
there are other expressions on the same line. If the next line is empty, returns t. If the port is
positioned at end of file, then it returns nil.
Arguments
p_inputPort Input port. Default is piport.
Values Returned
g_result The object read in.
nil When the port is at the end of file.
t If an empty line is encountered.
Example
Suppose the file SkillSyntaxFile.il contains the following expressions. Note that a
blank line follows the second expression:
define( x 1 )
define( y 2 )
procedure( add( x y ) x+y )
myPort = infile( "SkillSyntaxFile.il" )
=> port:SkillSyntaxFile.il"
read( myPort ) => define(x 1)
read( myPort ) => define(y 2)
read( myPort ) => t
read( myPort ) => procedure((add x y) (x + y ) )
read( myPort ) => nil
close( myPort ) => t
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readstring
readstring(
t_string
)
=> g_result | nil
Description
Returns the first expression in a string. Subsequent expressions in the string are ignored. The
expression is not processed in any way.
Arguments
t_string String to read.
Value Returned
g_result The object read in.
nil When the port is at the end of the string.
Example
readstring("fun( 1 2 3 ) fun( 4 5 )") => ( fun 1 2 3 )
The first example shows normal operation.
readstring("fun(" )
fun(
^
SYNTAX ERROR found at line 1 column 4 of file *string*
*Error* lineread/read: syntax error encountered in input
*WARNING* (include/load): expression was improperly terminated.
The second example shows the error message if the string contains a syntax error.
EXPRESSION = 'list( 1 2 )
=> list(1 2)
EXPRESSION == readstring( sprintf( nil "%L" EXPRESSION ))
=> t
The third example illustrates that readstring applied to the print representation of an
expression, returns the expression.
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readTable
readTable(
S_fileName
o_table
)
=> t | nil
Description
Reads and appends the contents of a file to an existing association table.
Prerequisites
The file submitted must have been created with the writeTable function so that the
contents are in a usable format.
Arguments
S_fileName File name (either a string or symbol) from which to read the data.
o_table Association table to which the file contents are appended.
Value Returned
t The data is read and appended.
nil Otherwise.
Example
myTable = makeTable("table1") => table:table1
myTable2 = makeTable("table2") => table:table2
myTable["three"] = 3 => 3
writeTable("table.out" myTable) => t
readTable("table.out" myTable2) => t
Reference
makeTable, writeTable
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realp
realp(
g_obj
)
=> t | nil
Description
Checks if a value is a real number. Same as floatp.
Arguments
g_obj Any SKILL object.
Value Returned
t Argument is a real number.
nil Argument is not a real number.
Example
realp( 2789987)
=> nil
realp( 2789.987)
=> t
Reference
floatp, integerp, fixp
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regExitAfter
regExitAfter(
s_name
)
=> t | nil
Description
Registers the action to be taken after the exit function has performed its bookkeeping tasks
but before it returns control to the operating system.
Arguments
s_name Name of the function that is to be added to the head of the list of
functions to be performed after the exit function.
Value Returned
t The function is added to the list of functions.
nil Otherwise.
Example
procedure( foo( @rest args)
println( "After proc being executed"))
regExitAfter( 'foo) => t
Reference
clearExitProcs, exit, regExitBefore, remExitProc
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regExitBefore
regExitBefore(
s_name
)
=> t
Description
Registers the action to be taken before the exit function is executed. If the function
registered returns the ignoreExit symbol, the exit is aborted.
Arguments
s_name Name of the function that is to be added to the head of the list of
functions to be executed before the exit function.
Value Returned
t Always.
Example
procedure( foo() println( "Aborting exit") 'ignoreExit)
=> foo
regExitBefore('foo)
=> t
exit ;Does not exit.
"Aborting exit"
procedure( foo() println( "Exiting"))
=> foo
exit ;Exits program.
"Exiting"
Reference
clearExitProcs, exit, regExitAfter, remExitProc
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remainder
remainder(
x_integer1
x_integer2
)
=> x_integer
Description
Returns the remainder of dividing two integers. The remainder is either zero or has the sign
of the dividend. Same as mod.
The remainder and modulo functions differ on negative arguments. The remainder is either
zero or has the sign of the dividend if you use the remainder function. With modulo the
return value always has the sign of the divisor.
Arguments
x_integer1 Dividend.
x_integer2 Divisor.
Value Returned
x_integer Remainder of dividing x_integer1 by x_integer2. The
sign is determined by the sign of x_integer1.
Example
modulo( 13 4) => 1
remainder( 13 4) => 1
modulo( -13 4) => 3
remainder( -13 4) => -1
modulo( 13 -4) => -3
remainder( 13 -4) => 1
modulo( -13 -4) => -1
remainder( -13 -4) => -1
Reference
mod, modulo
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remd
remd(
g_x
l_arg
)
=> l_result
Description
Removes all top-level elements equal to a SKILL object from a list. This is a destructive
removal
, which means that the original list itself is modified. Therefore, any other reference to
that list will also see the changes.
remd uses equal for comparison.
Caution
This is a destructive removal. The original list itself will be modified
except for the first element from the original list. Therefore, any other
reference to that list will also see the changes. See example 3 where the
same variable is used to hold the updated list.
Arguments
g_x Any SKILL object to be removed from the list.
l_arg List from which to remove g_x.
Value Returned
l_result Returns l_arg modified so that all top-level elements equal to
g_x are removed.
Example 1
y = '("a" "b" "x" "d" "f") => ("a" "b" "x" "d" "f")
remd( "x" y) => ("a" "b" "d" "f")
y => ("a" "b" "d" "f")
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Example 2
The first element from the original list will not be modified in-place.
y = '("a" "b" "d" "f") => ("a" "b" "d" "f")
remd( "a" y) => ("b" "d" "f")
y => ("a" "b" "d" "f")
Note the original list, y, is not modified.
Example 3
In order to remove the first element from the original list, use the same variable (that holds
the original list) to hold the updated list.
y = '("a" "b" "d" "f") => ("a" "b" "d" "f")
y=remd("a" y) => ("b" "d" "f")
y => ("b" "d" "f")
Reference
remdq, remove, remq
SKILL Language Reference
SKILL Language Functions
August 2005 389 Product Version 06.40
remdq
remdq(
g_x
l_arg
)
=> l_result
Description
Removes all top-level elements that are identical to a SKILL object using eq from a list. This
is a destructive removal, which means that the original list itself is modified. Therefore, any
other reference to that list will also see the changes.
remdq uses eq instead of equal for comparison.
Caution
This is a destructive removal, which means that the original list itself is
modified. Therefore, any other reference to that list will also see the
changes.
Arguments
g_x Any SKILL object to be removed from the list.
l_arg List from which to remove g_x.
Value Returned
l_result Returns l_arg modified so that all top-level elements eqto g_x
are removed.
Example
y = '(a b x d f x g) => (a b x d f x g)
remdq('x y) => (a b d f g)
y => (a b d f g)
SKILL Language Reference
SKILL Language Functions
August 2005 391 Product Version 06.40
remExitProc
remExitProc(
s_name
)
=> t
Description
Removes a registered exit procedure.
When SKILL exits, the function is not called.
Prerequisites
The exit procedure must have been previously registered with the regExitBefore or
regExitAfter function.
Arguments
s_name Name of the registered exit procedure to be removed.
Value Returned
t Always.
Example
remExitProc( 'endProc) => t
Reference
exit, regExitAfter, regExitBefore
SKILL Language Reference
SKILL Language Functions
August 2005 392 Product Version 06.40
remove
remove(
g_x
l_arg
)
=> l_result
remove(
g_key
o_table
)
=> g_value
Description
Returns a copy of a list with all top-level elements equal to a SKILL object removed. Can
also be used to remove an entry from an association table, in which case the removal is
destructive, that is, any other reference to the table will also see the changes.
remove uses equal for comparison.
remove can also be used with an association table to identify and remove an entry
corresponding to the key specified in the function.
Arguments
g_x Any SKILL object to be removed from the list.
l_arg List from which to remove g_x.
g_key Key or first element of the key/value pair.
o_table Association table containing the key/value pairs to be processed.
Value Returned
l_result Copy of l_arg with all top-level elements equal to g_x
removed.
g_value Value associated with the key that is removed.
SKILL Language Reference
SKILL Language Functions
August 2005 393 Product Version 06.40
Example
remove( "x" '("a" "b" "x" "d" "f"))
=> ("a" "b" "d" "f")
myTable = makeTable("myTable" -1)
=> table:myTable ;default is -1
myTable["two"]=2
=> 2
remove("two" myTable)
=> 2 ; permanently removed from table
myTable["two"]
=> -1 ; the default value
Reference
remd, remq
SKILL Language Reference
SKILL Language Functions
August 2005 394 Product Version 06.40
remprop
remprop(
sl_id
S_name
)
=> l_result | nil
Description
Removes a property from a property list and returns the property’s former value.
Arguments
sl_id Symbol or disembodied property list.
S_name Property name.
Value Returned
l_result Former value of the property as a single element list.
nil The property does not exist.
Example
putprop( 'chip 8 'pins ) => 8
Assigns the property pins to chip.
get( 'chip 'pins ) => 8
remprop( 'chip 'pins ) => (8)
Removes the property pins from chip.
get( 'chip 'pins) => nil
Reference
get, putprop
SKILL Language Reference
SKILL Language Functions
August 2005 395 Product Version 06.40
remq
remq(
g_x
l_arg
)
=> l_result
Description
Returns a copy of a list with all top-level elements that are identical to a SKILL object
removed. Uses eq.
Arguments
g_x Any SKILL object to be removed from the list.
l_arg List from which to remove g_x.
Value Returned
l_result A copy of l_arg with all top-level elements eq to g_x removed.
Example
remq('x '(a b x d f x g)) => (a b d f g)
Reference
remd, remdq, remove
SKILL Language Reference
SKILL Language Functions
August 2005 396 Product Version 06.40
renameFile
renameFile(
S_old
S_new
)
=> t | nil
Description:
The renameFile() function changes the name of a file or directory.The S_old argument
points to the pathname of the file or directory to be renamed. The S_new argument points to
the new pathname of the file or directory. If the SKILL path is nil, renameFile() would
search the current directory. Otherwise, the SKILL path would be searched first for S_old.
Note that a path which is anchored to current directory, for example, ./, ../,or../../..,
etc., is not considered as a relative path.
Arguments:
S_old Points to the pathname of the file or directory to be renamed.
S_new Points to the new pathname of the file or directory.
Value Returned
t File or directory is successfully re-named.
nil If S_old path does not exist.
Example
renameFile( "/usr/oldname" "/usr/newName" ) => t
renameFile( "/usr/old" "/usr/new" ) => nil ;if old does not exist.
renameFile( "old" "new" ) ;if old is a file while new is a directory
*Error* renameFile: is a directory
SKILL Language Reference
SKILL Language Functions
August 2005 397 Product Version 06.40
return
return(
[ g_result ]
)
=> g_result | nil
Description
Forces the enclosing prog to exit and returns the given value. The return statement has
meaning only when used inside a prog statement.
Both go and return are not purely functional in the sense that they transfer control in a non-
standard way. That is, they don’t return to their caller.
Arguments
g_result Any SKILL object.
Value Returned
The enclosing prog statement exits with the value given to return as the prog’s value. If
return is called with no arguments, nil is returned as the enclosing prog’s value.
Example
procedure( summation(l)
prog( (sum temp)
sum = 0
temp = l
while( temp
if( null(car(temp))
then
return(sum)
else
sum = sum + car(temp)
temp = cdr(temp)
)
)
)
)
Returns the summation of previous numbers if a nil is encountered.
summation( '(1 2 3 nil 4))
=> 6 ; 1+2+3
SKILL Language Reference
SKILL Language Functions
August 2005 399 Product Version 06.40
reverse
reverse(
l_arg
)
=> l_result
Description
Returns a copy of the given list with the elements in reverse order.
Because this function copies the list, it uses a lot of memory for large lists.
Arguments
l_arg A list.
Value Returned
l_result A new list with the elements at the top level in reverse order.
Example
reverse( '(1 2 3) ) => (3 2 1)
reverse( '(a b (c d) e) ) => '(e (c d) b a)
Reference
append, sort
SKILL Language Reference
SKILL Language Functions
August 2005 400 Product Version 06.40
rexCompile
rexCompile(
t_pattern
)
=> t | nil
Description
Compiles a regular expression string pattern into an internal representation to be used by
succeeding calls to rexExecute.
This allows you to compile the pattern expression once using rexCompile and then match
a number of targets using rexExecute; this gives better performance than using
rexMatchp each time.
Arguments
t_pattern Regular expression string pattern.
Value Returned
t The given argument is a legal regular expression string.
nil Signals an error if the given pattern is ill-formed or not a legal
expression.
Example
rexCompile("^[a-zA-Z]+") => t
rexCompile("\\([a-z]+\\)\\.\\1") => t
rexCompile("^\\([a-z]*\\)\\1$") => t
rexCompile("[ab")
=> *Error* rexCompile: Missing ] - "[ab"
Reference
rexExecute, rexMatchp, rexSubstitute
SKILL Language Reference
SKILL Language Functions
August 2005 401 Product Version 06.40
Pattern Matching of Regular Expressions
In many applications, you need to match strings or symbols against a pattern. SKILL provides
a number of pattern matching functions that are built on a few primitive C library routines with
a corresponding SKILL interface.
A pattern used in the pattern matching functions is a string indicating a regular expression.
Here is a brief summary of the rules for constructing regular expressions in SKILL:
Rules for Constructing Regular Expressions
Synopsis Meaning
c Any ordinary character (not a special character listed below) matches itself.
. A dot matches any character
.
\ A backslash when followed by a special character matches that character
literally. When followed by one of <, >, (, ), and 1,...,9, it has a special
meaning as described below.
[c...] A nonempty string of characters enclosed in square brackets (called a set)
matches one of the characters in the set. If the first character in the set is ^,
it matches a character not in the set. A shorthand S-E is used to specify a
set of characters S up to E, inclusive. The special characters ] and - have
no special meaning if they appear as the first character in a set.
* A regular expression of any of the forms above, followed by the closure
character * matches zero or more occurrences of that form.
+ Similar to *, except it matches one or more times.
\(...\) A regular expression wrapped as \( form \) matches whatever form
matches
, but saves the string matched in a numbered register (starting
from one, can be up to nine) for later reference
.
\n A backslash followed by a digit n matches the contents of the nth register
from the current regular expression.
\<...\> A regular expression starting with a \< and/or ending with a \> restricts the
pattern matching to the beginning and/or the end of a word. A word defined
to be a character string can consist of letters, digits, and underscores.
rs A composite regular expression rs matches the longest match of r followed
by a match for s.
^, $ A ^ at the beginning of a regular expression matches the beginning of a
string. A $ at the end matches the end of a string. Used elsewhere in the
pattern, ^ and $ are treated as ordinary characters.
SKILL Language Reference
SKILL Language Functions
August 2005 402 Product Version 06.40
How Pattern Matching Works
The mechanism for pattern matching
■ Compiles a pattern into a form and saves the form internally.
■ Uses that internal form in every subsequent matching against the targets until the next
pattern is supplied.
The rexCompile function does the first part of the task, that is, the compilation of a pattern.
The rexExecute function takes care of the second part, that is, actually matching a target
against the previously compiled pattern. Sometimes this two-step interface is too low-level
and awkward to use, so functions for higher-level abstraction (such as rexMatchp) are also
provided in SKILL.
Avoiding Null and Backslash Problems
■ A null string ("") is interpreted as no pattern being supplied, which means the previously
compiled pattern is still used. If there was no previous pattern, an error is signaled.
■ To put a backslash character (\) into a pattern string, you need an extra backslash (\) to
escape the backslash character itself.
For example, to match a file name with dotted extension .il, the pattern “^[a-zA-Z]+\\.il$” can
be used, but “^[a-zA-Z]\.il$” gives a syntax error. However, if the pattern string is read in from
an input function such as gets that does not interpret backslash characters specifically, you
should not add an extra backslash to enter a backslash character.
SKILL Language Reference
SKILL Language Functions
August 2005 403 Product Version 06.40
rexExecute
rexExecute(
S_target
)
=> t | nil
Description
Matches a string or symbol against the previously compiled pattern set up by the last
rexCompile call.
This function is used in conjunction with rexCompile for matching multiple targets against
a single pattern.
Arguments
S_target String or symbol to be matched. If a symbol is given, its print
name is used.
Value Returned
t A match is found.
nil Otherwise.
Example
rexCompile("^[a-zA-Z][a-zA-Z0-9]*") => t
rexExecute('Cell123) => t
rexExecute("123 cells") => nil
Target does not begin with a-z/A-Z
rexCompile("\\([a-z]+\\)\\.\\1") => t
rexExecute("abc.bc") => t
rexExecute("abc.ab") => nil
Reference
rexCompile, rexMatchp, rexSubstitute
SKILL Language Reference
SKILL Language Functions
August 2005 404 Product Version 06.40
rexMagic
rexMagic(
[ g_state ]
)
=> t | nil
Description
Turns on or off the special interpretation associated with the meta-characters in regular
expressions.
By default the meta-characters (^, $, *, +, \, [, ], etc.) in a regular expression are interpreted
specially. However, this “magic” can be explicitly turned off and on programmatically by this
function. If no argument is given, the current setting is returned. Users of vi will recognize
this as equivalent to the set magic/set nomagic commands.
Arguments
g_state nil turns off the magic of the meta-characters. Anything else
turns on the magic interpretation.
Value Returned
t The current setting.
nil The given argument.
Example
rexCompile( "^[0-9]+" ) => t
rexExecute( "123abc" ) => t
rexSubstitute( "got: \\0") => "got: 123"
rexMagic( nil ) => nil
rexCompile( "^[0-9]+" ) => t recompile w/o magic
rexExecute( "123abc" ) => nil
rexExecute( "**^[0-9]+!**") => t
rexSubstitute( "got: \\0") => "got: \\0"
rexMagic( t )=> t
rexSubstitute( "got: \\0") => "got: ^[0-9]+"
SKILL Language Reference
SKILL Language Functions
August 2005 406 Product Version 06.40
rexMatchAssocList
rexMatchAssocList(
t_pattern
l_targets
)
=> l_results | nil
Description
Returns a new association list created out of those elements of the given association list
whose key matches a regular expression pattern. The supplied regular expression pattern
overwrites the previously compiled pattern and is used for subsequent matching until the next
new pattern is provided.
l_targets is an association list, that is, each element on l_targets is a list with its
car taken as a key (either a string or a symbol). This function matches the keys against
t_pattern, selects the elements on l_targets whose keys match the pattern, and
returns a new association list out of those elements.
Arguments
t_pattern Regular expression pattern.
l_targets Association list whose keys are strings and/or symbols.
Value Returned
l_results New association list of elements that are in l_targets and
whose keys match t_pattern.
nil If no match is found. Signals an error if the given pattern is ill-
formed.
Example
rexMatchAssocList("^[a-z][0-9]*$"
'((abc "ascii") ("123" "number") (a123 "alphanum")
(a12z "ana")))
=> ((a123 "alphanum"))
SKILL Language Reference
SKILL Language Functions
August 2005 408 Product Version 06.40
rexMatchList
rexMatchList(
t_pattern
l_targets
)
=> l_results | nil
Description
Creates a new list of those strings or symbols in the given list that match a regular expression
pattern. The supplied regular expression pattern overwrites the previously compiled pattern
and is used for subsequent matching until the next new pattern is provided.
Arguments
t_pattern Regular expression pattern.
l_targets List of strings and/or symbols to be matched against the pattern.
Value Returned
l_results List of strings (or symbols) that are on l_targets and found to
match t_pattern.
nil If no match is found. Signals an error if the given pattern is ill-
formed.
Example
rexMatchList("^[a-z][0-9]*" '(a01 x02 "003" aa01 "abc"))
=> (a01 x02 aa01 "abc")
rexMatchList("^[a-z][0-9][0-9]*"
'(a001 b002 "003" aa01 "abc"))
=> (a001 b002)
rexMatchList("box[0-9]*" '(square circle "cell9" "123"))
=> nil
Reference
rexCompile, rexExecute, rexMatchAssocList, rexMatchp
SKILL Language Reference
SKILL Language Functions
August 2005 409 Product Version 06.40
rexMatchp
rexMatchp(
t_pattern
S_target
)
=> t | nil
Description
Checks to see if a string or symbol matches a given regular expression pattern. The supplied
regular expression pattern overwrites the previously compiled pattern and is used for
subsequent matching until the next new pattern is provided.
This function matches S_target against the regular expression t_pattern and returns
t if a match is found, nil otherwise. An error is signaled if the given pattern is ill-formed. For
greater efficiency when matching a number of targets against a single pattern, use the
rexCompile and rexExecute functions.
Arguments
t_pattern Regular expression pattern.
S_target String or symbol to be matched against the pattern.
Value Returned
t A match is found. Signals an error if the given pattern is ill-
formed.
Example
rexMatchp("[0-9]*[.][0-9][0-9]*" "100.001") => t
rexMatchp("[0-9]*[.][0-9]+" ".001") => t
rexMatchp("[0-9]*[.][0-9]+" ".") => nil
rexMatchp("[0-9]*[.][0-9][0-9]*" "10." => nil
rexMatchp("[0-9" "100")
*Error* rexMatchp: Missing ] - "[0-9"
Reference
rexCompile, rexExecute
SKILL Language Reference
SKILL Language Functions
August 2005 410 Product Version 06.40
rexReplace
rexReplace(
t_source
t_replacement
x_index
)
=> t_result
Description
Returns a copy of the source string in which the specified substring instances that match the
last compiled regular expression are replaced with the given string.
Scans the source string t_source to find all substring(s) that match the last regular
expression compiled and replaces one or all of them by the replacement string
t_replacement. The argument x_index tells which occurrence of the matched
substring is to be replaced. If it’s 0 or negative, all the matched substrings will be replaced.
Otherwise only the x_index occurrence is replaced. Returns the source string if the
specified match is not found.
Arguments
t_source Source string to be matched and replaced.
t_replacement Replacement string to be used. Pattern tags can be used in this
string (see rexSubstitute).
x_index Specifies which of the matching substrings to replace. Do a
global replace if it’s <= 0.
Value Returned
t_result Copy of the source string with specified replacement or the
original source string if no match was found.
Example
rexCompile( "[0-9]+" ) => t
rexReplace( "abc-123-xyz-890-wuv" "(*)" 1)
=> "abc-(*)-xyz-890-wuv"
SKILL Language Reference
SKILL Language Functions
August 2005 411 Product Version 06.40
rexReplace( "abc-123-xyz-890-wuv" "(*)" 2)
=> "abc-123-xyz-(*)-wuv"
rexReplace( "abc-123-xyz-890-wuv" "(*)" 3)
=> "abc-123-xyz-890-wuv"
rexReplace( "abc-123-xyz-890-wuv" "(*)" 0)
=> "abc-(*)-xyz-(*)-wuv"
rexCompile( "xyz" ) => t
rexReplace( "xyzzyxyzz" "xy" 0)
=> "xyzyxyz" ; no rescanning!
Reference
rexCompile, rexExecute, rexMatchp, rexSubstitute
SKILL Language Reference
SKILL Language Functions
August 2005 412 Product Version 06.40
rexSubstitute
rexSubstitute(
t_string
)
=> t_result | nil
Description
Substitutes the pattern tags in the argument string with previously matched (sub)strings.
Copies the argument string and substitutes all pattern tags in it by their corresponding
matched strings in the last string matching operation. The tags are in the form of ’\n’, where
n is 0-9. ’\0’ (or ’&’) refers to the string that matched the entire regular expression and \k refers
to the string that matched the pattern wrapped by the k’th \(...\) in the regular expression.
Arguments
t_string Argument string to be substituted.
Value Returned
t_result Copy of the argument with all the tags in it being substituted by
the corresponding strings.
nil The last string matching operation failed (and none of the pattern
tags are meaningful).
Example
rexCompile( "[a-z]+\\([0-9]+\\)" ) => t
rexExecute( "abc123" ) => t
rexSubstitute( "*\\0*" ) => "*abc123*"
rexSubstitute( "The matched number is: \\1" )
=> "The matched number is: 123"
rexExecute( "123456" ) => nil ; match failed
rexSubstitute( "-\\0-") => nil
Reference
rexCompile, rexExecute, rexReplace
SKILL Language Reference
SKILL Language Functions
August 2005 413 Product Version 06.40
rightshift
rightshift(
x_val
x_num
)
=> x_result
Description
Returns the integer result of shifting a value a specified number of bits to the right. Prefix form
of the >> arithmetic operator. Note that rightshift is logical (that is, vacated bits are 0-
filled).
Arguments
x_val Value to be shifted.
x_num Number of bits x_val is shifted.
Value Returned
x_result Result of the operation.
Example
rightshift(7 2) => 1
rightshift(10 1) => 5
Reference
leftshift
SKILL Language Reference
SKILL Language Functions
August 2005 414 Product Version 06.40
rindex
rindex(
t_string1
S_string2
)
=> t_result | nil
Description
Returns a string consisting of the remainder of string1 beginning with the last occurrence
of string2.
Compares two strings. Similar to index except that it looks for the last (that is, rightmost)
occurrence of the symbol or string S_string2 in string t_string instead of the first
occurrence.
Arguments
t_string1 String to search for the last occurrence of S_string2.
S_string2 String or symbol to search for.
Value Returned
t_result Remainder of t_string1 starting with last match of
S_string2.
nil There is no match.
Example
rindex( "dandelion" "d") => "delion"
Reference
index, nindex
SKILL Language Reference
SKILL Language Functions
August 2005 415 Product Version 06.40
round
round(
n_arg
)
=> x_result
Description
Rounds a floating-point number to its closest integer value.
Arguments
n_arg Floating-point number.
Value Returned
x_result Integer whose value is closest to n_arg.
Example
round(1.5) => 2
round(-1.49) => -1
round(1.49) => 1
Reference
fix, float
SKILL Language Reference
SKILL Language Functions
August 2005 416 Product Version 06.40
rplaca
rplaca(
l_arg1
g_arg2
)
=> l_result
Description
Replaces the first element of a list with an object. This function does not create a new list; it
alters the input list. Same as setcar.
Caution
This is a destructive operation, meaning that any other reference to the
list will also see the change.
Arguments
l_arg1 A list.
g_arg2 Any SKILL object.
Value Returned
l_result Modified l_arg1 with the car of l_arg1 replaced by
g_arg2.
Example
x = '(a b c)
rplaca( x 'd ) => (d b c)
x => (d b c)
The car of x is replaced by the second argument.
Reference
car, rplacd, setcar, setcdr
SKILL Language Reference
SKILL Language Functions
August 2005 417 Product Version 06.40
rplacd
rplacd(
l_arg1
l_arg2
)
=> l_result
Description
Replaces the tail of a list with the elements of a second list. This function does not create a
new list; it alters the input list. Same as setcdr.
Caution
This is a destructive operation, meaning that any other reference to the
list will also see the changes.
Arguments
l_arg1 List that is modified.
l_arg2 List that replaces the cdr of l_arg1.
Value Returned
l_result Modified l_arg1 with the cdr of the list l_arg1 replaced with
l_arg2.
Example
x = '(a b c)
rplacd( x '(d e f)) => (a d e f)
x => (a d e f)
The cdr of x is replaced by the second argument.
Reference
cdr, rplaca, setcar, setcdr
SKILL Language Reference
SKILL Language Functions
August 2005 418 Product Version 06.40
schemeTopLevelEnv
schemeTopLevelEnv(
)
=> e_envobj
Description
Returns the top level SKILL++ environment as an environment object.
Arguments
None.
Value Returned
e_envobj The top level SKILL++ environment object.
Example
schemeTopLevelEnv() => envobj:0x1ad018
Reference
envobj, theEnvironment - SKILL++ mode only
SKILL Language Reference
SKILL Language Functions
August 2005 419 Product Version 06.40
set
set(
s_variableName
g_newValue
[ e_environment ]
)
=> g_result
Description
Sets a variable to a new value. Similar to setq but the first argument for set is evaluated.
The set function is similar to the setq function, but unlike setq, the first argument for set
is evaluated. This argument must evaluate to a symbol, whose value is then set to
g_newValue.
Arguments
s_variableName Symbol that is evaluated.
g_newValue Value to set symbol to.
e_environment If this argument is given, SKILL++ semantics is assumed. The
forms entered will be evaluated within the given (lexical)
environment.
Value Returned
g_result Returns g_newValue.
Example
y = 'a => a ; Sets y to the constant a.
set y 5 => 5 ; Sets the value of y to 5.
y => a
a => 5
Reference
setq
SKILL Language Reference
SKILL Language Functions
August 2005 420 Product Version 06.40
setarray
setarray(
a_array
x_index
g_value
)
=> g_value
setarray(
o_table
g_key
g_value
)
=> g_value
Description
Assigns the given value to the specified element of an array or to the specified key of a table.
Normally this function is invoked implicitly using the array-subscription syntax, such as, x[i] =
v.
Assigns g_value to the x_index element of a_array, or adds the association of
g_value with g_key to o_table, and returns g_value. Normally this function is invoked
implicitly using the array-subscription syntax, such as, x[i] = v.
Arguments
a_array An array object.
x_index Index of the array element to assign a value to. Must be between
0 and one less than the size of the array.
g_key Any SKILL value.
g_value Value to be assigned to the specified array element or table
entry.
Value Returned
g_value Value assigned to the specified array element or table entry.
SKILL Language Reference
SKILL Language Functions
August 2005 421 Product Version 06.40
Example
declare(myar[8]) => array[8]:3895304
myar[0] => unbound
setarray(myar 0 5) => 5
myar[0] => 5
setarray(myar 8 'hi)
Signals an array bounds error.
setarray(myar
(plus 1 2) ; assigns element 3 the value 8.
(plus 3 5)) => 8
mytab = makeTable('myTable) => table:myTable
setarray(mytab 8 4) => 4
mytab[8] => 4
mytab[9] = 3 => 3 ; same as setarray(mytab 9 3)
mytab[9] => 3
Reference
arrayref, declare
SKILL Language Reference
SKILL Language Functions
August 2005 422 Product Version 06.40
setcar
setcar(
l_arg1
g_arg2
)
=> l_result
Description
Replaces the first element of a list with an object. Same as rplaca.
Caution
This is a destructive operation, meaning that any other reference to the
list will also see the change.
Arguments
l_arg1 A list.
g_arg2 A SKILL object.
Value Returned
l_result Modified l_arg1 with the car of l_arg1 replaced by
g_arg2.
Example
x = '(a b c) => (a b c)
setcar( x 'd ) => (d b c)
x => (d b c)
The car of x is replaced by the second argument.
Reference
car, rplaca, rplacd, setcdr
SKILL Language Reference
SKILL Language Functions
August 2005 423 Product Version 06.40
setcdr
setcdr(
l_arg1
l_arg2
)
=> l_result
Description
Replaces the tail of a list with the elements of a second list. Same as rplacd.
Caution
This is a destructive operation, meaning that any other reference to the
list will also see the change.
Arguments
l_arg1 List that is modified.
l_arg2 List that replaces the cdr of l_arg1.
Value Returned
l_result Modified l_arg1 with the cdr of the list l_arg1 replaced with
l_arg2.
Example
x = '(a b c)
setcdr( x '(d e f)) => (a d e f)
x => (a d e f)
The cdr of x is replaced by the second argument.
Reference
cdr, rplaca, rplacd, setcar
SKILL Language Reference
SKILL Language Functions
August 2005 424 Product Version 06.40
setFnWriteProtect
setFnWriteProtect(
s_name
)
=> t | nil
Description
Prevents a named function from being redefined.
If s_name has a function value, it can no longer be changed. If it does not have a function
value but does have an autoload property, the autoload is still allowed. This is treated as a
special case so that all the desired functions can be write-protected first and autoloaded as
needed.
Arguments
s_name Name of the function.
Value Returned
t The function is now write protected.
nil If the function is already write protected.
Example
Define a function and set its write protection so it cannot be redefined.
procedure( test() println( "Called function test" ))
setFnWriteProtect( 'test ) => t
procedure( test() println( "Redefine function test" ))
*Error* def: function name already in use and cannot be
redefined - test
setFnWriteProtect( 'plus ) => nil
Returns nil because the plus function is already write protected.
Reference
getFnWriteProtect, setVarWriteProtect - SKILL mode only
SKILL Language Reference
SKILL Language Functions
August 2005 425 Product Version 06.40
setof
setof(
s_formalVar
l_valueList
g_predicateExpression
)
=> l_result
setof(
s_formalVar
o_table
g_predicateExpression
)
=> l_result
Description
Returns a new list containing only those elements in a list or the keys in an association table
that satisfy an expression. This is a syntax form.
The setof form can also be used to identify all keys in an association table that satisfy the
specified expression.
Arguments
s_formalVar Local variable that is usually referenced in
g_predicateExpression.
l_valueList List of elements that are bound to s_formalVar one at a time.
g_predicateExpression
SKILL expression that usually uses the value of s_formalVar.
o_table Association table whose keys are bound to s_formalVar one
at time.
Value Returned
l_result New list containing only those elements in l_valueList that
satisfy g_predicateExpression, or list of all keys that
satisfy the specified expression.
SKILL Language Reference
SKILL Language Functions
August 2005 426 Product Version 06.40
Example
setof( x '(1 2 3 4) (x > 2) ) => (3 4)
setof( x '(1 2 3 4) (x < 3) ) => (1 2)
myTable = makeTable("atable" 0) => table:atable
myTable["a"]="first" => "first"
myTable["b"]=2 => 2
setof(key myTable (and (stringp key)(stringp myTable[key])))
=> ("a")
Reference
exists, foreach
SKILL Language Reference
SKILL Language Functions
August 2005 427 Product Version 06.40
setplist
setplist(
s_atom
l_plist
)
=> l_plist
Description
Sets the property list of an object to a new property list; the old property list attached to the
object is lost.
Caution
Users are strongly discouraged from using setplist because it might
remove vital properties being used by the system or other applications.
Arguments
s_atom A symbol.
l_plist New property list to attach to s_atom.
Value Returned
l_plist New property list for s_atom; the old property list is lost.
Example
setplist( 'chip '(pins 8 power 5) ) => (pins 8 power 5)
plist( 'chip ) => (pins 8 power 5)
chip.power => 5
Reference
getq, getqq, plist, putpropq, putpropqq, remprop
SKILL Language Reference
SKILL Language Functions
August 2005 428 Product Version 06.40
setPrompts
setPrompts(
s_prompt1
s_prompt2
)
=> t | nil
Description
Sets the prompt text string for the CIW. The first prompt is used to indicate the topmost top-
level. The second prompt is used whenever a nested top-level is entered.
The text string for s_prompt2 should always be the %d format string, which behaves the
same as the printf() format string, such that the nesting level of a nested top-level will be
shown as it deepens.
Note: Changing prompts in some applications can seriously interfere with their functioning;
be very careful using this function.
Arguments
Value Returned
Example
> setPrompts("~> " "<%d>> ")
t
~> toplevel( ’ils )
ILS-<2>> toplevel( ’ils )
ILS-<3>>
Sets the topmost top-level to ~> and the nested top-level to <%d>> :
> setPrompts("~> " "<%s>> ")
*Error* setPrompts: setPrompts expected %d not %s in prompt --
<%s>>
s_prompt1 Prompt text string.
s_prompt2 Prompt text string.
t The prompt has been set.
nil Returns nil and issues an error message if the prompt is not
changed.
SKILL Language Reference
SKILL Language Functions
August 2005 430 Product Version 06.40
setq
setq(
s_variableName
g_newValueExp
)
=> g_result
setq(
s_variableName = g_newValue
)
=> g_result
Description
Sets a variable to a new value. setq is the same as the assignment (=) operator. This is a
syntax form.
The symbol s_variableName is bound to the value of g_newValueExp. Note that the
first argument to setq is not evaluated but the second one is.
Arguments
s_variableName Variable to be bound.
g_newValueExp Expression to be evaluated and bound to s_variableName.
Value Returned
g_result Evaluated result of g_newValueExp is returned.
Example
x = 5 => 5
Assigns the value 5 to the variable x.
setq( x 5 ) => 5
Assigns the value 5 to the variable x.
y = 'a => a
Assigns the symbol a to the variable y.
SKILL Language Reference
SKILL Language Functions
August 2005 432 Product Version 06.40
setqbitfield1
setqbitfield1(
s_var
x_val
x_bitPosition
)
=> x_result
Description
Sets a value into a single bit in the bit field specified by the variable s_var, stores the new
value back into the variable, and then returns the new value. Prefix form of the <>= operator.
Arguments
s_var Variable representing the bit field whose value is to be changed.
x_val New value of the bit.
x_bitPosition Position of the bit whose value you are changing.
Value Returned
x_result New value of s_var.
Example
x = 0b1001
setqbitfield1(x 1 1) => 11
x => 11
setqbitfield1(x 1 2) => 15
x => 15
Reference
bitfield1, bitfield, setqbitfield
SKILL Language Reference
SKILL Language Functions
August 2005 433 Product Version 06.40
setqbitfield
setqbitfield(
s_var
x_val
x_msb
x_lsb
)
=> x_result
Description
Sets a value into a set of bits in the bit field specified by the variable s_var, stores the new
value back into the variable, and then returns the new value. Prefix form of the <:>= operator.
Arguments
s_var Variable representing the bit field whose value is to be changed.
x_val New value of the bit.
x_msb Leftmost bit of the set of bits whose value is to be changed.
x_lsb Rightmost bit of the set of bits whose value is to be changed.
Value Returned
x_result New value of s_var.
Example
x = 0
setqbitfield(x 0b1001 3 0) => 9
x => 9
setqbitfield(x 1 2 1) => 11
x => 11
setqbitfield(x 0 3 2) => 3
x => 3
Reference
bitfield1, bitfield, setqbitfield1
SKILL Language Reference
SKILL Language Functions
August 2005 434 Product Version 06.40
setShellEnvVar
setShellEnvVar(
t_UnixShellVariableExpr
)
=> t | nil
Description
Sets the value of a UNIX environment variable to a new value.
Arguments
t_UnixShellVariableExpr
Name of the UNIX shell environment variable and the new value,
separated by an equals sign.
Value Returned
t If the shell environment variable was set.
nil If the shell environment variable was not set.
Example
setShellEnvVar("PWD=/tmp”) => t
Sets the parent working directory to the /tmp directory .
getShellEnvVar("PWD") => "/tmp"
Gets the parent working directory.
Reference
csh, getShellEnvVar, sh, shell
SKILL Language Reference
SKILL Language Functions
August 2005 435 Product Version 06.40
setSkillPath
setSkillPath(
{tl_paths | nil }
)
=> l_strings | nil
Description
Sets the internal SKILL path used by some file-related functions in resolving relative path
names.
You can specify the directory paths either in a single string, separated by spaces, or as a list
of strings. The system tests the validity of each directory path as it puts the input into standard
form. If all directory paths exist, it returns nil.
If any path does not exist, a list is returned in which each element is an invalid path. Note that
■ The directories on the SKILL path are always searched for in the order you specified in
tl_paths.
■ Even if a path does not exist (and hence appears in the returned list) it remains on the
new SKILL path.
The use of the SKILL path in other file-related functions can be effectively disabled by calling
setSkillPath with nil as the argument.
Arguments
tl_paths Directory paths specified either in a single string or list of strings.
nil Turns off the use of the SKILL path.
Value Returned
l_strings List of directory paths that appear in the tl_paths argument
but do not actually exist.
nil If all directory paths exist.
SKILL Language Reference
SKILL Language Functions
August 2005 436 Product Version 06.40
Example
setSkillPath('("." "~" "~/cpu/test1"))
=> nil ; If "~/cpu/test1" exists.
=> ("~/cpu/test1") ; If "~/cpu/test1" does not exist.
The same task can be done with the following call that puts all paths in one string.
setSkillPath(". ~ ~/cpu/test1")
Reference
getSkillPath, prependInstallPath
SKILL Language Reference
SKILL Language Functions
August 2005 437 Product Version 06.40
setVarWriteProtect - SKILL mode only
setVarWriteProtect(
s_name
)
=> t | nil
Description
Sets the write-protection on a variable to prevent its value from being updated. Does not work
in SKILL++ mode.
Use this function in SKILL mode only when the variable and its contents are to remain
constant.
■ If the variable has a value, it can no longer be changed.
■ If the variable does not have a value, it cannot be used.
■ If the variable holds a list or other data structure as its value, it is assumed that the
contents will not be changed. If you try to update the contents, the behavior is
unspecified.
In SKILL++ mode, use setFnWriteProtect instead.
Arguments
s_name Name of variable to be write-protected.
Value Returned
t Variable is write protected.
nil Variable was already write protected.
Example
y = 5 ; Initialize the variable y.
setVarWriteProtect( 'y )=> t ; Set y to be write protected.
setVarWriteProtect( 'y )=> nil ; Already write protected.
y = 10 ; y is write protected.
*Error* setq: Variable is protected and cannot be
assigned to - y
SKILL Language Reference
SKILL Language Functions
August 2005 439 Product Version 06.40
sh, shell
sh(
[ t_command ]
)
=> t | nil
shell(
[ t_command ]
)
=> t | nil
Description
Starts the UNIX Bourne shell sh as a child process to execute a command string.
If the sh function is called with no arguments, an interactive UNIX shell is invoked that
prompts you for UNIX command input (available only in nongraphic applications).
Arguments
t_command Command string.
Value Returned
t If the exit status of executing the given shell command is 0.
nil Otherwise.
Example
shell( rm /tmp/junk)
Removes the junk file from the /tmp directory and returns t if it is removed successfully.
Reference
csh, getShellEnvVar, setShellEnvVar
SKILL Language Reference
SKILL Language Functions
August 2005 440 Product Version 06.40
simplifyFilename
simplifyFilename(
t_name
[ g_dontResolveLinks ]
)
=> t_result
Description
Expands the name of a file to its full path.
Returns the fully expanded name of the file t_name. Tilde expansion is performed, “./” and
“../” are compressed, and redundant slashes are removed. By default, symbolic links are also
resolved, unless the second (optional) argument g_notResolveLinks is specified to
non-nil.
If t_name is not absolute, the current working directory is prefixed to the returned file name.
Arguments
t_name File to be fully expanded.
g_dontResolveLinks If specified to non-nil, symbolic links are not resolved.
Value Returned
t_result Fully expanded name of the file.
Example
simplifyFilename(“~/test”) => “/usr/mnt/user/test”
Assumes the user’s home directory is /usr/mnt/user.
simplifyFilename( "/tmp/fileName" t) => "/tmp/fileName"
Assumes /tmp/fileName is a symbolic link of /tmp/fileName.real.
Reference
isDir, isFileName, prependInstallPath
SKILL Language Reference
SKILL Language Functions
August 2005 441 Product Version 06.40
sin
sin(
n_number
)
=> f_result
Description
Returns the sine of a floating-point number or integer.
Arguments
n_number Floating-point number or integer.
Value Returned
f_result Sine of n_number.
Example
sin(3.14/2) => 0.9999997
sin(3.14159/2) => 1.0
Floating point results from evaluating the same expressions may be machine dependent.
Reference
acos, asin, cos
SKILL Language Reference
SKILL Language Functions
August 2005 442 Product Version 06.40
sort
sort(
l_data
u_comparefn
)
=> l_result
Description
Sorts a list according to a comparison function; defaults to an alphabetical sort when
u_comparefn is nil. This function does not create a new list. It returns the altered input
list. This is a destructive operation. The l_data list is modified in place and no new storage
is allocated. Pointers previously pointing to l_data may not be pointing at the head of the
sorted list.
Sorts the list l_data according to the sortfunction u_comparefn. u_comparefn( g_x
g_y ) returns non-nil if g_x can precede g_y in sorted order, nil if g_y must precede
g_x. If u_comparefn is nil, alphabetical order is used. The algorithm currently
implemented in sort is based on recursive merge sort.
Caution
The l_data list is modified in place and no new storage is allocated.
Pointers previously pointing to l_data may not be pointing at the head of
the sorted list.
Arguments
l_data List of objects to be sorted.
u_comparefn Comparison function to determine which of any two elements
should come first.
Value Returned
l_result l_data sorted by the comparison function u_comparefn.
SKILL Language Reference
SKILL Language Functions
August 2005 443 Product Version 06.40
Example
y = '(c a d b)
(sort y nil) => (a b c d)
y => (c d) ;no longer points to head of list
y = '(c a d b)
y = (sort y nil) => (a b c d)
y => (a b c d) ;reassignment points y to sorted list.
Reference
alphalessp, lessp, sortcar
SKILL Language Reference
SKILL Language Functions
August 2005 444 Product Version 06.40
sortcar
sortcar(
l_data
u_comparefn
)
=> l_result
Description
Similar to sort except that only the car of each element in a list is used for comparison by
the sort function. This function does not create a new list. It returns the altered input list.
This function also sorts l_data based on the function u_comparefn.
Caution
The l_data list is modified in place and no new storage is allocated.
Pointers previously pointing to l_data might not be pointing at the head
of the sorted list.
Arguments
l_data List of objects to be sorted.
u_comparefn Comparison function to determine which of any two elements
should come first.
Value Returned
l_result l_data sorted by the comparison function u_comparefn.
Example
sortcar( '((4 four) (3 three) (2 two)) 'lessp )
=> ((2 two) (3 three) (4 four)
sortcar( '((d 4) (b 2) (c 3) (a 1)) nil )
=> ((a 1) (b 2) (c 3) (d 4))
SKILL Language Reference
SKILL Language Functions
August 2005 446 Product Version 06.40
sprintf
sprintf(
{s_Var | nil }
t_formatString
[ g_arg1 ... ]
)
=> t_string
Description
Formats the output and assigns the resultant string to the variable given as the first argument.
This is a syntax form
Refer to the “
Common Output Format Specifications” table on the fprintf manual page. If
nil is specified as the first argument, no assignment is made, but the formatted string is
returned.
Arguments
s_Var Variable name.
nil nil if no variable name.
t_formatString Format string.
g_arg1 Arguments following the format string are printed according to
their corresponding format specifications.
Value Returned
t_string Formatted output string.
Example
sprintf(s "Memorize %s number %d!" "transaction" 5)
=> "Memorize transaction number 5!"
s
=> "Memorize transaction number 5!"
p = outfile(sprintf(nil "test%d.out" 10))
=> port:"test10.out"
SKILL Language Reference
SKILL Language Functions
August 2005 448 Product Version 06.40
sqrt
sqrt(
n_number
)
=> f_result
Description
Returns the square root of a floating-point number or integer.
Arguments
n_number Floating-point number or integer.
Value Returned
f_result Square root of the value passed in.
If the value of n_number is not a positive number, an error is
signaled.
Example
sqrt( 49 )
=> 7.0
sqrt( 43942 )
=> 209.6235
SKILL Language Reference
SKILL Language Functions
August 2005 450 Product Version 06.40
sstatus
sstatus(
s_name
g_switchValue
)
=> g_switchValue
Description
Sets the internal system variable named to a given value. This is a syntax form.
The internal variables are typically Boolean switches that accept only the Boolean values of
t and nil. Efficiency and security are the reasons why these system variables are stored as
internal variables that can only be set by sstatus, rather than as SKILL variables you can
set directly.
Internal System Variables
Name Meaning Default
autoReload If t, the debugger will try to auto-reload a file that is not
loaded under debugMode when the user tries to single step
into the code defined by that file. Note: this may not work
correctly for SKILL++ functions defined using assignment.
nil
debugMode Debug mode provides more information for debugging
SKILL programs. Allows you to redefine write-protected
SKILL functions.
nil
errsetTrace Prints errors and stacktrace information that is normally
suppressed by errset.
nil
fullPrecision If t, unformatted print functions (print, println,
printlev) print floating point numbers in full precision
(usually 16 digits); otherwise, the default is about 7 digits of
precision.
nil
integermode When on (default is off), the parser translates all arithmetic
operators into calls to functions that operate only on
fixnums. This results in small execution time savings and
makes sense only for compute-intensive tasks whose inner
loops are dominated by integer arithmetic calculations.
nil
SKILL Language Reference
SKILL Language Functions
August 2005 451 Product Version 06.40
mergemode When on (default), arithmetic expressions are merged by
the parser whenever possible into a minimum number of
function calls and therefore run somewhat faster because
most of the arithmetic functions such as plus,
difference, times, and quotient can accept a
variable number of arguments.
t
printinfix Printing of arithmetic expressions and function calls in
infix notation is turned off (on) if the second argument is
nil (t).
t
writeProtect When on, all functions being defined have their write
protection set to t so they cannot be redefined.
When off, all functions being defined for the first time are
not write-protected and thus can be redefined. When
developing SKILL code, be sure this switch is set to off.
nil
stacktraceDump Prints the local variables when an error occurs if sstatus(
stacktrace t) is set. Toggle on/off with t / nil.
nil
stacktrace Prints stack frames every time an error occurs. Toggle on/
off with t / nil, or set the number of frames to display.
0
sourceTracing If t, the debugger will try to print out the corresponding
source location at stop/breakpoints (as well as in stack
tracing). A file must be loaded in when debugMode is set to
t in order to get its source line numbers. The source forms
printed are truncated to fit on one line.
nil
traceArgs If set to non-nil, the system will save the evaluated
arguments of function calls, which can then be displayed in
the stacktrace.
Setting debugMode or tracing functions (using tracef) will
no longer turn on traceArgs automatically. The default
behavior is to turn off this switch because it is very
expensive to keep the evaluated arguments around all the
time.
Note: turning on this switch could slow down the execution
speed significantly.
nil
Internal System Variables
Name Meaning Default
SKILL Language Reference
SKILL Language Functions
August 2005 452 Product Version 06.40
Arguments
s_name Name of internal system variable.
g_switchValue New value for internal system variable, usually t or nil.
Value Returned
g_switchValue The second argument to sstatus.
Example
sstatus( debugMode t ) => t
Turns on debug mode.
sstatus( integermode t ) => t
Turns on integer mode.
sstatus( stacktraceDump t) => t
Prints the local variables when an error occurs if
sstatus( stacktrace t) is set.
sstatus( stacktrace 6 ) => 6
Prints the first six stack frames every time an error occurs.
Reference
status
SKILL Language Reference
SKILL Language Functions
August 2005 453 Product Version 06.40
status
status(
s_name
)
=> g_switchValue
Description
Returns the value of the internal system variable named. This nlambda function also works
in SKILL++ mode.
See the sstatus function for a
list of the internal system variables.
Arguments
s_name Name of internal system variable.
Value Returned
g_switchValue Status of the internal system variable, usually either t or nil.
Example
status( debugMode ) => t
Checks the status of debugMode and returns t if debugMode is on.
The status function gets a switch. The sstatus function sets a switch.
status debugMode ; read the current value of the switch
=> nil
sstatus debugMode t ; set the value of the switch to new value
=> t
status debugMode
=> t
Reference
sstatus
SKILL Language Reference
SKILL Language Functions
August 2005 454 Product Version 06.40
strcat
strcat(
S_string1
[ S_string2 ... ]
)
=> t_result
Description
Takes input strings or symbols and concatenates them.
Arguments
S_string1 S_string2 ...
One or more input strings or symbols.
Value Returned
t_result New string containing the contents of all input strings or symbols
S_string1, S_string2, ..., concatenated together.
The input arguments are left unchanged.
Example
strcat( 'ab "xyz" ) => "abxyz"
strcat( "l" "ab" "ef" ) => "labef"
Reference
buildString, concat, strncat, strcmp, strncmp, substring
SKILL Language Reference
SKILL Language Functions
August 2005 455 Product Version 06.40
strcmp
strcmp(
t_string1
t_string2
)
=> 1 | 0 | -1
Description
Compares two argument strings alphabetically.
Compares the two argument strings t_string1 and t_string2 and returns an integer
greater than, equal to, or less than zero depending on whether t_string1 is alphabetically
greater, equal to, or less than t_string2. To simply test if the contents of two strings are
the same, use the equal function.
Arguments
t_string1 First string to be compared.
t_string2 Second string to be compared.
Value Returned
1 t_string1 is alphabetically greater than t_string2.
0 t_string1 is alphabetically equal to t_string2.
-1 t_string1 is alphabetically less than t_string2.
Example
strcmp( "abc" "abb" ) => 1
strcmp( "abc" "abc") => 0
strcmp( "abc" "abd") => -1
Reference
equal, strncmp
SKILL Language Reference
SKILL Language Functions
August 2005 456 Product Version 06.40
stringp
stringp(
g_value
)
=> t | nil
Description
Checks if an object is a string.
The suffix pis usually added to the name of a function to indicate that it is a predicate function.
Arguments
g_value A data object.
Value Returned
t g_value is a string.
nil Otherwise.
Example
stringp( 93)
=> nil
stringp( "93")
=> t
Reference
listp, symbolp
SKILL Language Reference
SKILL Language Functions
August 2005 457 Product Version 06.40
stringToFunction
stringToFunction(
t_string
[ s_langMode ]
)
=> u_function
Description
Wraps and converts a string of SKILL code into a parameterless SKILL function.
Parses the given string argument and wraps the result with a parameterless lambda, then
compiles the entire form into a function object. The returned function can later be applied
with better performance than direct evaluation using evalstring.
Arguments
t_string String representing some SKILL code.
s_langMode Must be a symbol.
Valid values:
Value Returned
u_function Parameterless function equivalent to evaluating the string
(lambda( ) t_string).
Example
f = stringToFunction("1+2") => funobj:0x220038
apply(f nil) => 3
Reference
evalstring, apply
'ils Treats the string as SKILL++ code.
'il Treats the string as SKILL code.
SKILL Language Reference
SKILL Language Functions
August 2005 458 Product Version 06.40
stringToSymbol
stringToSymbol(
t_string
)
=> s_symbolName
Description
Converts a string to a symbol of the same name.
Arguments
t_string String to convert to a symbol.
Value Returned
s_symbolName Symbol for the given string.
Example
y = stringToSymbol( "test")
=> test
sprintf(nil "%L" y)
=> "test"
Reference
concat, symbolToString
SKILL Language Reference
SKILL Language Functions
August 2005 459 Product Version 06.40
stringToTime
stringToTime(
t_time
)
=> x_time
Description
Given a date and time string, returns an integer time value representation. The time argument
must be in the format as returned by the timeToString function, such as: Dec 28
16:57:06 1996.
All time conversion functions assume local time, not GMT time.
Arguments
t_time String indicating a time and date in this format: "Dec 28
16:57:06 1996". Same as format returned by timeToString
or getCurrentTime.
Value Returned
x_time Integer time value.
Example
fileTimeModified( "~/.cshrc" )
=> 793561559
timeToString(793561559)
=> "Feb 23 09:45:59 1995"
stringToTime("Feb 23 09:45:59 1995")
=> 793561559
Reference
getCurrentTime, timeToString, timeToTm, tmToTime
SKILL Language Reference
SKILL Language Functions
August 2005 460 Product Version 06.40
strlen
strlen(
t_string
)
=> x_length
Description
Returns the number of characters in a string.
Arguments
t_string String length you want to obtain.
Value Returned
x_length Length of t_string.
Example
strlen( "abc" ) => 3
strlen( "\007" ) => 1 ; Backslash notation used.
Reference
index, parseString, substring, strcat, strcmp, strncmp, stringp
SKILL Language Reference
SKILL Language Functions
August 2005 461 Product Version 06.40
strncat
strncat(
t_string1
t_string2
x_max
)
=> t_result
Description
Creates a new string by appending a maximum number of characters from t_string2 to
t_string1.
Concatenates input strings. Similar to strcat except that at most x_max characters from
t_string2 are appended to the contents of t_string1 to create the new string.
t_string1 and t_string2 are left unchanged.
Arguments
t_string1 First string included in the new string.
t_string2 Second string whose characters are appended to t_string1.
x_max Maximum number of characters from t_string2 that you want
to append to the end of t_string1.
Value Returned
t_result The new string; t_string1 and t_string2 are left
unchanged.
Example
strncat( "abcd" "efghi" 2) => "abcdef"
strncat( "abcd" "efghijk" 5) => "abcdefghi"
Reference
parseString, strcat, strcmp, strncmp, substring, stringp
SKILL Language Reference
SKILL Language Functions
August 2005 462 Product Version 06.40
strncmp
strncmp(
t_string1
t_string2
x_max
)
=> 1 | 0 | -1
Description
Compares two argument strings alphabetically only up to a maximum number of characters.
Similar to strcmp except that only up to x_max characters are compared. To simply test if
the contents of two strings are the same, use the equal function.
Arguments
t_string1 First string to be compared.
t_string2 Second string to be compared.
x_max Maximum number of characters in both strings to be compared.
Value Returned
For the first specified number of characters:
1 t_string1 is alphabetically greater than t_string2
0 t_string1 is alphabetically equal to t_string2.
-1 t_string1 is alphabetically less than t_string2.
Example
strncmp( "abc" "ab" 3) => 1
strncmp( "abc" "de" 4) => -1
strncmp( "abc" "ab" 2) => 0
SKILL Language Reference
SKILL Language Functions
August 2005 464 Product Version 06.40
sub1
sub1(
n_number
)
=> n_result
Description
Subtracts one from a floating-point number or integer.
Arguments
n_number Floating-point number or integer.
Value Returned
n_result n_number minus one.
Example
sub1( 59 )
=> 58
Reference
add1
SKILL Language Reference
SKILL Language Functions
August 2005 465 Product Version 06.40
subst
subst(
g_x
g_y
l_arg
)
=> l_result
Description
Substitutes one object for another object in a list.
Arguments
g_x Object substituted.
g_y Object substituted for.
l_arg A list.
Value Returned
l_result Result of substituting g_x for all equal occurrences of g_y at
all levels in l_arg.
Example
subst( 'a 'b '(a b c) ) => (a a c)
subst('x 'y '(a b y (d y (e y)))) => (a b x (d x (e x )))
Reference
remd
SKILL Language Reference
SKILL Language Functions
August 2005 466 Product Version 06.40
substring
substring(
S_string
x_index
[ x_length ]
)
=> t_result | nil
Description
Creates a new substring from an input string, starting at an index point and continuing for a
given length.
Creates a new substring from S_string with a starting point determined by x_index and
length determined by an optional third argument x_length.
■ If S_string is a symbol, the substring is taken from its print name.
■ If x_length is not given, then all of the characters from x_index to the end of the
string are returned.
■ If x_index is negative the substring begins at the indexed character from the end of the
string.
■ If x_index is out of bounds (that is, its absolute value is greater than the length of
S_string), nil is returned.
Arguments
S_string A string.
x_index Starting point for returning a new string. Cannot be zero.
x_length Length of string to be returned.
Value Returned
t_result Substring of S_string starting at the character indexed by
x_index, with a maximum of x_length characters.
nil If x_index is out of bounds.
SKILL Language Reference
SKILL Language Functions
August 2005 468 Product Version 06.40
sxtd
sxtd(
x_number
x_bits
)
=> x_result
Description
Sign-extends the number represented by the rightmost specified number of bits in the given
integer.
Sign-extends the rightmost x_bits bits of x_number. That is, sign-extends the bit field
x_number<x_bits - 1:0> with x_number<x_bits - 1> as the sign bit.
Arguments
x_number An integer.
x_bits Number of bits.
Value Returned
x_result x_number with the rightmost x_bits sign-extended.
Example
sxtd( 7 4 ) => 7
sxtd( 8 4 ) => -8
sxtd( 5 2 ) => 5
Reference
zxtd
SKILL Language Reference
SKILL Language Functions
August 2005 469 Product Version 06.40
symbolp
symbolp(
g_value
)
=> t | nil
Description
Checks if an object is a symbol.
The suffix pis usually added to the name of a function to indicate that it is a predicate function.
Arguments
g_value A data object.
Value Returned
t If g_value is a symbol.
nil Otherwise.
Example
symbolp( 'foo) => t
symbolp( "foo") => nil
symbolp( concat("foo")) => t
Reference
concat, stringp
SKILL Language Reference
SKILL Language Functions
August 2005 470 Product Version 06.40
symbolToString
symbolToString(
s_symbolName
)
=> t_string
Description
Converts a symbol to a string of the same name. Same as get_pname.
Arguments
s_symbolName Symbol to convert.
Value Returned
t_string String with the same name as the input symbol.
Example
y = symbolToString( 'test2)
=> "test2"
sprintf(nil "%L" y)
=> "\"test2\""
Reference
get_pname, stringToSymbol
SKILL Language Reference
SKILL Language Functions
August 2005 471 Product Version 06.40
symeval
symeval(
s_symbol
[ e_environment ]
)
=> g_result
Description
Returns the value of the named variable.
symeval is slightly more efficient than eval and can be used in place of eval when you are
sure that the argument being evaluated is indeed a variable name.
Arguments
s_symbol Name of the variable.
e_environment If this argument is given, SKILL++ semantics is assumed. The
variable name will be looked up within the given (lexical)
environment.
Value Returned
g_result Value of the named variable.
Example
x = 5
symeval( 'x ) => 5
symeval( 'y ) => unbound ;Assumes y is unbound.
Reference
eval
SKILL Language Reference
SKILL Language Functions
August 2005 472 Product Version 06.40
symstrp
symstrp(
g_value
)
=> t | nil
Description
Checks if an object is either a symbol or a string.
The suffix pis usually added to the name of a function to indicate that it is a predicate function.
Arguments
g_value A data object.
Value Returned
t If g_value is either a symbol or a string.
nil Otherwise.
Example
symstrp( "foo" ) => t
symstrp( 'foo ) => t
symstrp( 3 ) => nil
Reference
stringp, symbolp
SKILL Language Reference
SKILL Language Functions
August 2005 473 Product Version 06.40
system
system(
t_command
)
=> x_result
Description
Spawns a separate UNIX process to execute a command.
Arguments
t_command Command to execute.
Value Returned
x_result The return code caused by executing the given UNIX command.
Example
system( "date" )
Wed Dec 14 15:14:53 PST 1994
0
system( "daa" )
sh: daa: not found
1
Reference
csh, sh, shell
SKILL Language Reference
SKILL Language Functions
August 2005 474 Product Version 06.40
tablep
tablep(
g_object
)
=> t | nil
Description
Checks if an object is an association table.
Arguments
g_object A SKILL object.
Value Returned
t If g_object is an association table.
nil If g_object is not an association table.
Example
myTable = makeTable("atable1" 0) => table:atable1
tablep(myTable) => t
tablep(9) => nil
Reference
makeTable
SKILL Language Reference
SKILL Language Functions
August 2005 475 Product Version 06.40
tableToList
tableToList(
o_table
)
=> l_assoc_list
Description
Converts the contents of an association table to an association list. Use this function
interactively to look at the contents of a table.
Note: This function eliminates the efficiency that you gain from referencing data in an
association table. Do not use this function for processing data in an association table. Instead,
use this function interactively to look at the contents of a table.
Arguments
o_table Association table to be converted.
Value Returned
l_assoc_list Association list containing key/value pairs from the association
table.
Example
myTable = makeTable( "table" 0) => table:table
myTable[ "first"] = 1 => 1
myTable[ 'two] = 2 => 2
tableToList(myTable) => ((two 2)("first" 1))
Reference
makeTable, tablep
SKILL Language Reference
SKILL Language Functions
August 2005 476 Product Version 06.40
tailp
tailp(
l_arg1
l_arg2
)
=> l_arg1 | nil
Description
Returns arg1 if a list cell eq to arg1 is found by cdr down arg2 zero or more times, nil
otherwise.
Because eqis being used for comparison l_arg1 must actually point to a tail list in l_arg2
for this predicate to return a non-nil value.
Arguments
l_arg1 A list.
l_arg2 Another list, which can contain l_arg1 as its tail.
Value Returned
l_arg If a list cell eq to l_arg1 is found by cdr’ing down l_arg2
zero or more times.
nil Otherwise.
Example
y = '(b c)
z = cons( 'a y ) => (a b c)
tailp( y z ) => (b c)
tailp( '(b c) z ) => nil
nil was returned because '(b c) is not eq the cdr( z ).
Reference
cdr, eq
SKILL Language Reference
SKILL Language Functions
August 2005 477 Product Version 06.40
tan
tan(
n_number
)
=> f_result
Description
Returns the tangent of a floating-point number or integer.
Arguments
n_number Floating-point number or integer.
Value Returned
f_result Tangent of n_number.
Example
tan( 3.0 ) => -0.1425465
Reference
atan, cos, sin
SKILL Language Reference
SKILL Language Functions
August 2005 478 Product Version 06.40
tconc
tconc(
l_ptr
g_x
)
=> l_result
Description
Creates a list cell whose car points to a list of the elements being constructed and whose
cdr points to the last list cell of the list being constructed.
A tconc structure is a special type of list that allows efficient addition of objects to the end of
a list. It consists of a list cell whose car points to a list of the elements being constructed with
tconcand whose cdrpoints to the last list cell of the list being constructed. If l_ptr is nil,
anewtconc structure is automatically created. To obtain the list under construction, take the
car of the tconc structure.
tconc and lconc are much faster than append when adding new elements to the end of a
list. The append function is much slower, because it traverses and copies the list to reach the
end, whereas tconc and lconc only manipulate pointers.
l_ptr A tconc structure. Must be initialized to nil to create a new
tconc structure.
g_x Element to add to the end of the list.
Value Returned
l_result Returns l_ptr, which must be a tconc structure or nil, with
g_x added to the end.
Example
x = tconc(nil 1) ; x is now ((1) 1)
tconc(x 2) ; x is now ((1 2) 2)
tconc(x 3) ; x is now ((1 2 3) 3)
x = car(x) ; x is now (1 2 3)
x now equals (1 2 3), the desired result.
SKILL Language Reference
SKILL Language Functions
August 2005 480 Product Version 06.40
theEnvironment - SKILL++ mode only
theEnvironment(
[ u_funobj ]
)
=> e_environment | nil
Description
Returns the top level environment if called from a SKILL++ top-level. Returns the enclosing
lexical environment if called within a SKILL++ function. Returns the associated environment
if passed a SKILL++ function object. Otherwise returns nil.
■ In SKILL++, there is a unique top-level environment that implicitly encloses all other local
environments. If you do not pass the optional argument, when you call
theEnvironment from a SKILL++ top-level, theEnvironment returns this
environment. The schemeTopLevelEnv function also returns this environment.
■ If you call theEnvironment from within a SKILL++ function and if you do not pass the
optional argument, theEnvironment returns the enclosing lexical environment.
■ If you are in debug mode, you can pass a closure to theEnvironment. A closure is
another term for a function object returned by evaluating a SKILL++ lambda expression
which abstractly, consists of two parts:
❑ The code for the lambda expression.
❑ The environment in which the free variables in the body are bound when the lambda
expression is evaluated.
■ If you call theEnvironment from a SKILL function and do not pass a closure, then
theEnvironment function returns nil.
Arguments
u_funobj Optional argument. Should be a SKILL++ closure.
Value Returned
nil Returned when called from a SKILL function and you do not pass
a SKILL++ closure as the optional argument.
SKILL Language Reference
SKILL Language Functions
August 2005 481 Product Version 06.40
e_environment Either the top-level environment, or the enclosing environment,
or the closure’s environment.
Example
Z = let( ( x )
x = 3
theEnvironment()
) ; let
=> envobj:0x1e0060
Returns the environment that the let expression establishes. The value of Z is an
environment in which x is bound to 3. Each time you execute the above expression, it returns
a different environment object, as you can tell by observing the print representation.
Z = let( (( x theEnvironment()))
x
)
=> envobj:0x2fc018
eq( schemeTopLevelEnv() Z ) => t
Uses theEnvironment to illustrate that the variable initialization expressions in a let
expression refer to the enclosing environment.
V = letrec( (( x theEnvironment()))
x
)
=> envobj:0x33506c
eq( schemeTopLevelEnv() V ) => nil
eq( V~>x V ) => t
Uses theEnvironment to illustrate that the variable initialization expressions in a letrec
expression refers to the letrec’s environment.
W = let( (( r 3 ) ( y 4 ))
let( (( z 5 ) ( v 6 ))
theEnvironment()
) ; let
) ; let
=> envobj:0x456030c
W~>r => 3
W~>z => 5
W~>?? => ((z(5) (v 6)) ((r 3) y(4)))
Returns the environment that the nested let expressions establish. Notice that assigning it
to the top-level variable W makes it persistent.
Q = letrec(
( ;; begin locals
( X 6 )
( self
lambda( ( )
theEnvironment()
) ; lambda
) ; self
) ;;; end of locals
SKILL Language Reference
SKILL Language Functions
August 2005 482 Product Version 06.40
self
) ; letrec
=> funobj:0x1e38b8
Q() => envobj:0x1e00e4
theEnvironment( Q ) => envobj:0x1e00e4 ;in debug mode only
Returns a function object which, in turn, returns its local environment.
Reference
schemeTopLevelEnv, envobj, funobj
SKILL Language Reference
SKILL Language Functions
August 2005 483 Product Version 06.40
times
times(
n_op1
n_op2
[ n_op3 ... ]
)
=> n_result
Description
Returns the result of multiplying the first operand by one or more operands. Prefix form of the
* arithmetic operator.
Arguments
n_op1 First operand to be multiplied.
n_op2 Second operand to be multiplied.
n_op3 Optional additional operands to be multiplied.
Value Returned
n_result Result of the multiplication.
Example
times(5 4 3 2 1) => 120
times(-12 -13) => 156
times(12.2 -13.3) => -162.26
Reference
xtimes
SKILL Language Reference
SKILL Language Functions
August 2005 484 Product Version 06.40
timeToString
timeToString(
x_time
)
=> t_time
Description
Takes an integer UNIX time value, returns a formatted string that the value denotes. The
string is always in a form like: Dec 28 16:57:06 1994.
Arguments
x_time Integer time value.
Value Returned
t_time Formatted string the value denotes.
Example
fileTimeModified( "~/.cshrc" )
=> 793561559
timeToString(793561559)
=> "Feb 23 09:45:59 1995"
stringToTime("Feb 23 09:45:59 1995")
=> 793561559
Reference
fileTimeModified, stringToTime, timeToTm
SKILL Language Reference
SKILL Language Functions
August 2005 485 Product Version 06.40
timeToTm
timeToTm(
x_time
)
=> r_tm
Description
Given an integer time value, returns a tm structure.
r_tm is a defstruct similar to POSIX's tm struct:
struct tm {
int tm_sec; /* seconds after the minute: [0, 61] */
int tm_min; /* minutes after the hour: [0, 59] */
int tm_hour; /* hours after midnight: [0, 23] */
int tm_mday; /* day of the month: [1, 31] */
int tm_mon; /* month of the year: [0, 11] */
int tm_year; /* year since 1900 */
int tm_wday; /* days since Sunday: [0, 6] */
int tm_yday; /* days since January: [0, 365] */
int tm_isdst; /* daylight saving time flag: <0,0,>0*/
};
■ Use x->?? to get all its fields.
■ Use x->tm_sec and so forth to access individual fields.
All time conversion functions assume local time, not GMT time.
Arguments
x_time Integer time value.
Value Returned
r_tm A defstruct similar to POSIX's tm struct.
Example
fileTimeModified( "~/.cshrc" )
=> 793561559
timeToString(793561559)
=> "Feb 23 09:45:59 1995"
SKILL Language Reference
SKILL Language Functions
August 2005 487 Product Version 06.40
tmToTime
tmToTime(
r_tm
)
=> x_time
Description
Given a tm structure, returns the integer value of the time it represents.
r_tm is a defstruct similar to POSIX's tm struct:
struct tm {
int tm_sec; /* seconds after the minute: [0, 61] */
int tm_min; /* minutes after the hour: [0, 59] */
int tm_hour; /* hours after midnight: [0, 23] */
int tm_mday; /* day of the month: [1, 31] */
int tm_mon; /* month of the year: [0, 11] */
int tm_year; /* year since 1900 */
int tm_wday; /* days since Sunday: [0, 6] */
int tm_yday; /* days since January: [0, 365] */
int tm_isdst; /* daylight saving time flag: <0,0,>0*/
};
■ Use x->?? to get all its fields.
■ Use x->tm_sec and so forth to access individual fields.
All time conversion functions assume local time, not GMT time.
Arguments
r_tm A defstruct similar to POSIX's tm struct.
Value Returned
x_time Integer time value.
Example
fileTimeModified( "~/.cshrc" )
=> 793561559
timeToString(793561559)
=> "Feb 23 09:45:59 1995"
SKILL Language Reference
SKILL Language Functions
August 2005 488 Product Version 06.40
x = timeToTm(793561559)
=>array[11]:1702872
x->??
(tm_sec 59 tm_min 45 tm_hour
9 tm_mday 23 tm_mon 1
tm_year 95 tm_wday 4 tm_yday
53 tm_isdst 0
)
tmToTime(x)
=> 793561559
Reference
fileTimeModified, stringToTime, timeToString, timeToTm
SKILL Language Reference
SKILL Language Functions
August 2005 489 Product Version 06.40
truncate
truncate(
n_number
)
=> x_integer
Description
Truncates a given number to an integer.
Arguments
n_number Any SKILL number.
Value Returned
x_integer n_number truncated to an integer.
Example
truncate( 1234.567)
=> 1234
round( 1234.567)
=> 1235
truncate( -1.7)
=> -1
Reference
ceiling, floor, round
SKILL Language Reference
SKILL Language Functions
August 2005 490 Product Version 06.40
type, typep
type(
g_value
)
=> s_type | nil
typep(
g_value
)
=> s_type | nil
Description
Returns a symbol whose name denotes the type of a data object. The functions type and
typep are identical.
Arguments
g_value A data object.
Value Returned
s_type Symbol whose name denotes the type of g_value.
nil Otherwise.
Example
type( 'foo ) => symbol
typep( "foo" ) => string
Reference
fixp, floatp, numberp, portp, stringp, symbolp
SKILL Language Reference
SKILL Language Functions
August 2005 491 Product Version 06.40
unalias
unalias(
s_aliasName1 ...
)
=> l_result
Description
Undefines the aliases specified in an argument list and returns a list containing the aliases
undefined by the call. This is nlambda function also works in SKILL++ mode.
Caution
Use alias for interactive command entry only and never in programs.
Arguments
s_aliasName1 Symbol name of the alias.
Value Returned
l_result List of the aliases removed.
Example
alias path getSkillPath => path
Aliases path to the getSkillPath function.
unalias path => (path)
Removes path as an alias.
Reference
alias
SKILL Language Reference
SKILL Language Functions
August 2005 492 Product Version 06.40
unless
unless(
g_condition
g_expr1 ...
)
=> g_result | nil
Description
Evaluates a condition. If the result is true (non-nil), it returns nil; otherwise evaluates the
body expressions in sequence and returns the value of the last expression. This is a syntax
form.
The semantics of this function can be read literally as "unless the condition is true, evaluate
the body expressions in sequence".
Arguments
g_condition Any SKILL expression.
g_expr1 Any SKILL expression.
Value Returned
g_result Value of the last expression of the sequence g_expr1 if
g_condition evaluates to nil.
nil If g_condition evaluates to non-nil.
Example
x = -123
unless( x >= 0 println("x is negative") -x)
=> 123 ;Prints "x is negative" as side effect.
unless( x < 0 println("x is positive") x)
=> nil
Reference
cond, if, when
SKILL Language Reference
SKILL Language Functions
August 2005 493 Product Version 06.40
upperCase
upperCase(
S_string
)
=> t_result
Description
Returns a string that is a copy of the given argument with the lowercase alphabetic characters
replaced by their uppercase equivalents.
If the parameter is a symbol, the name of the symbol is used.
Arguments
S_string Input string or symbol.
Value Returned
t_result Copy of S_string in uppercase letters.
Example
upperCase("Hello world!") => "HELLO WORLD!"
Reference
lowerCase
SKILL Language Reference
SKILL Language Functions
August 2005 494 Product Version 06.40
vector
vector(
g_value ...
)
=> a_vectorArray
Description
Returns a vector, or array, filled with the arguments in the given order. The vector function
is analogous to the list function.
A vector is implemented as a SKILL array.
Arguments
g_value Ordered list of values to be placed in an array.
Value Returned
a_vectorArray Array filled with the arguments in the given order.
Example
V = vector( 1 2 3 4 ) => array[4]:33394440
V[0] => 1
V[3] => 4
Reference
declare, list, listToVector, makeVector, vectorToList
SKILL Language Reference
SKILL Language Functions
August 2005 495 Product Version 06.40
vectorp
vectorp(
g_value
)
=> t | nil
Description
Checks if an object is a vector. Behaves the same as arrayp.
The suffix pis usually added to the name of a function to indicate that it is a predicate function.
Arguments
g_value Any data object.
Value Returned
t If g_value is a vector object.
nil Otherwise.
Example
declare(x[10])
arrayp(x) => t
arrayp('x) => nil
Reference
declare, arrayp
SKILL Language Reference
SKILL Language Functions
August 2005 496 Product Version 06.40
vectorToList
vectorToList(
a_vectorArray
)
=> l_list
Description
Returns a list containing the elements of an array.
Arguments
a_vectorArray Vector to be converted.
Value Returned
l_list List constructed from the given vector.
Example
vectorToList( vector( 1 2 3 ) )
=> ( 1 2 3 )
vectorToList( makeVector( 3 "Hi"))
=> ("Hi" "Hi""Hi")
Reference
declare, vector, listToVector, makeVector
SKILL Language Reference
SKILL Language Functions
August 2005 497 Product Version 06.40
vi, vii, vil
vi(
[ S_fileName ]
)
=> t | nil
Description
Edits a file using the vi editor. This is an nlambda function. Edits the named file using the
vi editor, and optionally includes (vii) or loads (vil) the file into SKILL after exiting the
editor. These functions are just variants of ed, edi, and edl with explicit request for using
the vi editor.
Arguments
S_fileName File to edit. If no argument is given, defaults to the previously
edited file, or temp.il, if there is no previous file.
Value Returned
t If the operation was successfully completed.
nil If the file does not exit or there is an error condition.
Example
vil( "test.il" )
vi()
Reference
ed, edi, edl, edit
SKILL Language Reference
SKILL Language Functions
August 2005 498 Product Version 06.40
warn
warn(
t_formatString
[ g_arg1 ... ]
)
=> nil
Description
Buffers a warning message with given arguments inserted using the same format
specification as sprintf, printf, and fprintf.
After a function returns to the top level, the buffered warning message is printed in the
Command Interpreter Window. Arguments to warn use the same format specification as
sprintf, printf, and fprintf.
This function is useful for printing SKILL warning messages in a consistent format. You can
also suppress a message with a subsequent call to getWarn.
Arguments
t_formatString Characters to print verbatim in the warning message with format
specifications prefixed by the percent (%) sign.
g_arg1 ... Optional arguments following the format string, which are printed
according to their corresponding format specifications.
Value Returned
nil Always returns nil.
Example
arg1 = 'fail
warn( "setSkillPath: first argument must be a string or list of strings - %s\n"
arg1)
=> nil
*WARNING* setSkillPath: first argument must be a string or list of strings - fail
SKILL Language Reference
SKILL Language Functions
August 2005 500 Product Version 06.40
when
when(
g_condition
g_expr1 ...
)
=> g_result | nil
Description
Evaluates a condition. If the result is non-nil, evaluates the sequence of expressions and
returns the value of the last expression. This is a syntax form.
If the result of evaluating g_condition is nil, when returns nil.
Arguments
g_condition Any SKILL expression.
g_expr1 Any SKILL expression.
Value Returned
g_result Value of the last expression of the sequence g_expr1 if
g_condition evaluates to non-nil.
nil If the g_condition expression evaluates to nil.
Example
x = -123
when( x < 0
println("x is negative")
-x)
=> 123 ;Prints "x is negative" as side effect.
when( x >= 0
println("x is positive")
x)
=> nil
Reference
cond, if, unless
SKILL Language Reference
SKILL Language Functions
August 2005 501 Product Version 06.40
which
which(
t_fileName
)
=> t_fullPath | nil
Description
Returns the absolute path of the given context file, or regular file or directory.
The main usage of this function is to load prerequisite context files.
If t_fileName identifies a context file (that is with the .cxt extension), it looks under the
standard contexts location (associated with the application in which this function is called), as
well as common Cadence contexts directory, your_install_path/tools/dfII/etc/
context, and user contexts location, youre_install_path/tools/dfII/local/
context, for the presence of the context file.
If t_fileName identifies a regular file or directory, the current SKILL path is searched. Note
that a path which is anchored to current directory, for example, ./, ../,or../../.., etc.,
is not considered as a relative path.
Arguments
t_fileName Name of a context file, or a regular file or directory that you want
to get the absolute path.
Value Returned
t_fullPath The absolute path of t_fileName.
nil If t_fileName is not found.
Example
Loading a prerequisite context file:
loadContext( which( "myPrereq.cxt" ) ) => t
Get the absolute path of a file:
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which( ".cdsinit" ) => "/usr/michaelc/.cdsinit"
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while
while(
g_condition
g_expr1 ...
)
=> t
Description
Repeatedly evaluates a condition and sequence of expressions until the condition evaluates
to false. This is a syntax form.
Repeatedly evaluates g_condition and the sequence of expressions g_expr1 ... if
the condition is true. This process is repeated until g_condition evaluates to false (nil).
Note that because this form always returns t, it is principally used for its side-effects.
Arguments
g_condition Any SKILL expression.
g_expr1 Any SKILL expression.
Value Returned
t Always returns t.
Example
i = 0
while( (i <= 10) printf("%d\n" i++) )
=> t
Prints the digits 0 through 10.
Reference
for, foreach
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write
write(
g_value
[ p_outputPort ]
)
=> nil
Description
Prints a SKILL object using the default format for the data type of the value.
For example, strings are enclosed in ". Same as print.
Arguments
g_value Any SKILL object.
p_outputPort Output port to print to. Default is poport.
Value Returned
nil Always returns nil, after it prints out the object supplied to it.
Example
for( i 1 3 write( "hello" )) ;Prints hello three times.
"hello""hello""hello"
=> t
Reference
display, pprint, print, println, printlev
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writeTable
writeTable(
S_fileName
o_table
)
=> t | nil
Description
Writes the contents of an association table to a file with one key/value pair per line.
Note: This function is for writing basic SKILL data types that are stored in an association
table. The function cannot write database objects or other user-defined types that might be
stored in association tables.
Arguments
S_fileName Name of the print file (either a string or symbol) to which the table
contents are to be written.
o_table Association table from which the data is accessed.
Value Returned
t If the data is successfully written to the file.
nil Otherwise.
Example
writeTable("inventory" myTable) => t
writeTable(noFile myTable) => nil
Reference
makeTable, readTable
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August 2005 506 Product Version 06.40
xcons
xcons(
l_list
g_element
)
=> l_result
Description
Adds an element to the beginning of a list. Equivalent to cons but the order of the arguments
is reversed.
Arguments
l_list A list, which can be nil.
g_element Element to be added to the beginning of l_list.
Value Returned
l_result Returns a list.
Example
xcons( '(b c) 'a ) => ( a b c )
Reference
append, append1, cons, lconc, list, ncons, tconc
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xCoord
xCoord(
l_list
)
=> g_result
Description
Returns the first element of a list. Does not modify the argument list.
Note: The xCoord and yCoord functions are aliases for the
car and cadr functions.
Arguments
l_list A list of elements.
Value Returned
g_result Returns the first element in a list.
Example
xValue = 300
yValue = 400
aCoordinate = xValue:yValue => ( 300 400 )
xCoord( aCoordinate ) => 300
yCoord( aCoordinate ) => 400
Reference
car
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xdifference
xdifference(
x_op1
x_op2
[ x_opt3 ]
)
=> x_result
Description
Returns the integer result of subtracting one or more operands from the first operand.
xdifference is an integer-only arithmetic function while difference can handle integers
and floating-point numbers. xdifference runs slightly faster than difference in integer
arithmetic calculation.
Arguments
x_op1 Operand from which one or more operands are subtracted.
x_op2 Operand to be subtracted.
x_opt3 Optional additional operands to be subtracted.
Value Returned
x_result Result of the subtraction.
Example
xdifference(12 13) => -1
xdifference(-12 13) => -25
Reference
difference
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August 2005 509 Product Version 06.40
xplus
xplus(
x_op1
x_op2
[ x_opt3 ]
)
=> x_result
Description
Returns the integer result of adding one or more operands to the first operand. xplus is an
integer-only arithmetic function while plus can handle integers and floating-point numbers.
xplus runs slightly faster than plus in integer arithmetic calculation.
Arguments
x_op1 First operand to be added.
x_op2 Second operand to be added.
x_opt3 Optional additional operands to be added.
Value Returned
x_result Result of the addition.
Example
xplus(12 13) => 25
xplus(-12 -13) => -25
Reference
plus
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xquotient
xquotient(
x_op1
x_op2
[ x_opt3 ]
)
=> x_result
Description
Returns the integer result of dividing the first operand by one or more operands. xquotient
is an integer-only arithmetic function while quotient can handle integers and floating-point
numbers. xquotient runs slightly faster than quotient in integer arithmetic calculation.
Arguments
x_op1 Dividend.
x_op2 Divisor.
x_opt3 Optional additional divisors.
Value Returned
x_result Result of the division.
Example
xquotient(10 2) => 5
xquotient(-10 -2) => 5
Reference
quotient
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August 2005 511 Product Version 06.40
xtimes
xtimes(
x_op1
x_op2
[ x_opt3 ]
)
=> x_result
Description
Returns the integer result of multiplying the first operand by one or more operands. xtimes
is an integer-only arithmetic function while times can handle integers and floating-point
numbers. xtimes runs slightly faster than times in integer arithmetic calculation.
Arguments
x_op1 First operand to be multiplied.
x_op2 Second operand to be multiplied.
x_opt3 Optional additional operands to be multiplied.
Value Returned
x_result Result of the multiplication.
Example
xtimes(12 13) => 156
xtimes(-12 -13) => 156
Reference
times
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August 2005 512 Product Version 06.40
yCoord
yCoord(
l_list
)
=> g_result
Description
Returns the tail of the list, that is, the list without its first element.
Note: The xCoord and yCoord functions are aliases for the
car and cadr functions.
Arguments
l_list A list of elements.
Value Returned
g_result Returns the end of a list, or the list minus the first element.
Example
xValue = 300
yValue = 400
aCoordinate = xValue:yValue => ( 300 400 )
xCoord( aCoordinate ) => 300
yCoord( aCoordinate ) => 400
Reference
cdr
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zerop
zerop(
n_num
)
=> t | nil
Description
Checks if a value is equal to zero.
zerop is a predicate function.
Arguments
n_num Number to check.
Value Returned
t If n_num is equal to zero.
nil Otherwise.
Example
zerop( 0 )
=> t
zerop( 7 )
=> nil
Reference
evenp, minusp, oddp, onep, plusp
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zxtd
zxtd(
x_number
x_bits
)
=> x_result
Description
Zero-extends the number represented by the rightmost specified number of bits in the given
integer.
Zero-extends the rightmost x_bits bits of x_number. Executes faster than doing
x_number<x_bits - 1:0>.
Arguments
x_number An integer.
x_bits Number of bits.
Value Returned
x_result x_number with the rightmost x_bits zero-extended.
Example
zxtd( 8 3 ) => 0
zxtd( 10 2 ) => 2
Reference
sxtd
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A
Scheme/SKILL++ Equivalents Tables
The purpose of this appendix is to help users familiar with Scheme to get a jump start with
SKILL++. All of Scheme’s special (syntax) forms and functions are listed along with their
SKILL++ equivalents.
The tables, which are divided into expressions, lexical structure, and functions, use these
terms:
See the following sections for more information:
■ Lexical Structure on page 516
■ Expressions on page 517
■ Functions on page 518
Same Means that this Scheme functionality is provided with the same
name (syntax) and same behavior in SKILL++.
Supported Means that this Scheme functionality is provided, but it is
implemented under a different name and/or is used somewhat
differently. For example,
(1) In SKILL++, the Scheme function make-vector becomes
makeVector.
(2) The global variable piport is used in place of the Scheme
function current-input-port.
Infix only Means that the specific Scheme functionality is provided, but the
given name can only be used as an infix operator in SKILL++.
There is usually an equivalent function with a different name to
which this infix operator can be mapped.
Unsupported Means that this Scheme functionality is not yet provided in
current SKILL++.
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Lexical Structure
Scheme/SKILL++ Equivalents Table – Lexical Structure
Scheme SKILL++ Comment
Boolean literals #t, #f Supported. Use t for #t, nil for #f.
Character literals
#\...
Unsupported. Character type not supported.
Simple numeric literals
such as integers &
floats
Supported. Use 0..., 0x..., and 0b... for #o..., #x...,
and #b... (octal/hex/binary integers).
String literals "..." Same.
Vector literals #(...) Same.
case-insensitive
symbols
Unsupported. Symbols in SKILL++ are always case-
sensitive.
nil as a symbol Unsupported. In SKILL++, just as in SKILL, nil is
not a symbol.
Special symbol
constituent characters
such as !, $, %, &, *, /,
<, =, and so forth.
Unsupported. Some of these are used for (infix)
operators in SKILL++, others are illegal
characters. ? is used for keyword
prefix.
' (single quote) Same. Shorthand for quote.
‘ (back quote) Same. Shorthand for quasiquote in
Scheme and for _backquote in
SKILL++.
, (comma) Same. Shorthand for unquote in Scheme
and for
_comma in SKILL++.
,@ Same. Shorthand for unquote-splicing in
Scheme and for _commaAt in
SKILL++.
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Expressions
Scheme/SKILL++ Equivalents Table – Expressions
Scheme SKILL++ Comment
(improper lists),
such as (d ... . d)
Unsupported. SKILL++ lists must end with nil.
(procedure calls),
such as (f e ...)
Same. Can be written as f(e ...) in
SKILL++ if f is a symbol (variable).
(and e ...) Same.
(begin e ...) Same. Equivalent to progn in SKILL++.
(case ((d ...) e ...) ...
[(else e ...)])
Same.
(cond (e ...) ... [(else e
...)])
Same.
(define x e)
(define (x v ...) body)
Same. One can also use SKILL’s procedure
syntax to define functions in SKILL++.
(do ((v e [e]) ...) (e ...) e
...)
Same.
(if e1 e2 e3) Same. SKILL++ allows extended if syntax
(with then and else keywords) as in
SKILL.
(lambda (x ...) body) Same. Improper variable list such as (x ...
. y) can’t be used as formals in
SKILL++. Use SKILL style @rest,
@optional instead.
(let [x] ((v e) ...) body) Same.
(let* ((v e) ...) body) Supported. Use letseq instead of let* in
SKILL++.
(letrec ((v e) ...) body) Same.
(or e ...) Same.
(set! x e) Supported. Use setq or the infix = operator.
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Functions
Scheme/SKILL++ Equivalents Table – Functions
Scheme SKILL++ Comment
+, -, *, / Infix only. Equivalent to functions plus,
difference, times, and quotient
in SKILL++.
<, <=, >, >= Infix only. Equivalent to functions lessp, leqp,
greaterp, and geqp in SKILL++.
= Supported. Note that = is used as the infix
assignment operator in SKILL++. For
equality, use the infix operator == or
function equal.
abs Same.
acos Same.
angle Unsupported.
append Same. Takes two arguments only.
apply Same.
asin Same.
assoc Same.
assq Same.
assv Same.
atan Same. In SKILL++, atan takes one argument
only; atan2 takes two arguments.
boolean? Supported. Use booleanp.
car, cdr, caar, ...,
cddddr
Same.
call-with-current-
continuation
Unsupported.
call-with-input-file Unsupported.
call-with-output-file Unsupported.
ceiling Same.
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char->integer Unsupported. True character type is not supported in
SKILL++. However, single-character
symbols can be used to simulate it.
The function charToInt has the
same effect on symbols.
char-alphabetic? Unsupported. Character type not supported.
char-ci<=? Unsupported. Character type not supported.
char-ci<? Unsupported. Character type not supported.
char-ci=? Unsupported. Character type not supported.
char-ci>=? Unsupported. Character type not supported.
char-ci>? Unsupported. Character type not supported.
char-downcase Unsupported. Character type not supported.
char-lower-case? Unsupported. Character type not supported.
char-numeric? Unsupported. Character type not supported.
char-upcase Unsupported. Character type not supported.
char-upper-case? Unsupported. Character type not supported.
char-whitespace? Unsupported. Character type not supported.
char<=? Unsupported. Character type not supported.
char<? Unsupported. Character type not supported.
char=? Unsupported. Character type not supported.
char>=? Unsupported. Character type not supported.
char>? Unsupported. Character type not supported.
char? Unsupported. Character type not supported.
close-input-port Supported. Use close.
close-output-port Supported. Use close.
complex? Unsupported.
cons Same. The second argument must be a list.
cos Same.
Scheme/SKILL++ Equivalents Table – Functions
Scheme SKILL++ Comment
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current-input-port Supported. Use the piport global variable.
current-output-port Supported. Use the poport global variable.
denominator Unsupported.
display Same.
eof-object? Unsupported. SKILL++ reader returns nil on EOF.
eq? Supported. Use eq.
equal? Supported. Use equal.
eqv? Supported. Use eqv.
even? Supported. Use evenp.
exact->inexact Unsupported.
exact? Unsupported.
exp Same.
expt Same.
floor Same. Use fix or floor.
for-each Supported. Use mapc.
gcd Unsupported.
imag-part Unsupported.
inexact->exact Unsupported.
inexact? Unsupported.
input-port? Supported. Use inportp.
integer->char Unsupported. Character type not supported. Use
intToChar for the same effect on
symbols.
integer? Supported. Use fixp or integerp.
lcm Unsupported.
length Same. Works for both lists and vectors.
list Same.
Scheme/SKILL++ Equivalents Table – Functions
Scheme SKILL++ Comment
SKILL Language Reference
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August 2005 521 Product Version 06.40
list->vector Supported. Use listToVector.
list-ref Supported. Use nth.
list? Supported. Use listp.
log Same.
magnitude Unsupported.
make-polar Unsupported.
make-rectangular Unsupported.
make-string Unsupported.
make-vector Supported. Use makeVector.
map Supported. Use mapcar instead. Note that map in
SKILL++ behaves differently from map
in standard Scheme.
max Same.
member Same.
memq Same.
memv Same.
min Same.
modulo Same. modulo differs from mod in SKILL++,
which is the same as remainder.
negative? Supported. Use minusp or negativep.
newline Same.
not Same. New for SKILL++. Same as ! operator.
null? Supported. Use null.
number->string Supported. Use sprintf.
number? Supported. Use numberp.
numerator Unsupported.
odd? Supported. Use oddp.
open-input-file Supported. Use infile.
Scheme/SKILL++ Equivalents Table – Functions
Scheme SKILL++ Comment
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open-output-file Supported. Use outfile.
output-port? Supported. Use outportp.
pair? Supported. Use dtpr or pairp.
peek-char Unsupported.
positive? Supported. Use plusp.
procedure? Supported. Use procedurep.
quotient Same.
rational? Unsupported.
rationalize Unsupported.
read Supported. Or use lineread. Returns nil on
EOF.
read-char Unsupported. Character type not supported. Use
getc for similar effect.
real-part Unsupported.
real? Supported. Use floatp or realp.
remainder Same. Use mod or remainder.
reverse Same.
round Same.
set-car! Supported. Use rplaca or setcar.
set-cdr! Supported. Use rplacd or setcdr.
sin Same.
sqrt Same.
string Unsupported.
string->number Supported. Use readstring.
string->symbol Supported. Use concat or stringToSymbol.
string-append Supported. Use strcat.
string-ci<=? Unsupported.
Scheme/SKILL++ Equivalents Table – Functions
Scheme SKILL++ Comment
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string-ci<? Unsupported.
string-ci>? Unsupported.
string-length Supported. Use strlen.
string-ref Unsupported. Use getchar for similar effect.
string-set! Unsupported. Strings in SKILL++ are immutable.
string<? Supported. Use alphalessp or strcmp.
string=? Supported. Use alphalessp or strcmp.
string>=? Supported. Use alphalessp or strcmp.
string>? Supported. Use alphalessp or strcmp.
string? Supported. Use stringp.
substring Supported. Argument values differ. SKILL++ uses
index and length. Scheme standard
uses start and end (index).
symbol->string Supported. Use get_pname or
symbolToString.
symbol? Supported. Use symbolp.
tan Same.
truncate Same.
vector Same.
vector-length Supported. Use length.
vector->list Supported. Use vectorToList.
vector-ref Supported. Use arrayref or the a[i] syntax.
vector-set! Supported. Use setarray or the a[i] = v
syntax.
vector? Supported. Use arrayp or vectorp.
write Same.
write-char Unsupported.
zero? Supported. Use zerop.
Scheme/SKILL++ Equivalents Table – Functions
Scheme SKILL++ Comment
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