CHANGESTR.REX: Difference between revisions
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(added functionality to this version of the CHANGESTR function, changed comments, indentation. -- ~~~~) |
m (updated some comments in this version of the BIF. -- ~~~~) |
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This version of the '''changestr''' BIF has more functionality than the standard BIF. |
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<lang rexx>/*REXX program emulates the CHANGESTR built-in function for older REXXes*/ |
<lang rexx>/*REXX program emulates the CHANGESTR built-in function for older REXXes*/ |
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/*──── This version has more functionality: limit the number of changes.*/ |
/*──── This version has more functionality: limit the number of changes.*/ |
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/*──── start of change |
/*──── start of change occurrence#.*/ |
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/*──── start of change position. */ |
/*──── start of change position. */ |
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/*╔══════════════════════════ CHANGESTR function ══════════════════════╗ |
/*╔══════════════════════════ CHANGESTR function ══════════════════════╗ |
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╔═╩════════════════════════════════════════════════════════════════════╩═╗ |
╔═╩════════════════════════════════════════════════════════════════════╩═╗ |
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║ The CHANGESTR function is used to replace some or all |
║ The CHANGESTR function is used to replace some or all occurrences of an║ |
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║ (old) string in a haystack with a new string. The changed string is ║ |
║ (old) string in a haystack with a new string. The changed string is ║ |
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║ returned. If the haystack doesn't contain the old string, the ║ |
║ returned. If the haystack doesn't contain the old string, the ║ |
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║ ║ |
║ ║ |
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║ new string to be used►──────────┐ ┌─────◄limit of # changes (times).║ |
║ new string to be used►──────────┐ ┌─────◄limit of # changes (times).║ |
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║ original string (haystack)►──────┐ │ │ [default: ≈ one |
║ original string (haystack)►──────┐ │ │ [default: ≈ one billion]║ |
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║ old string to be replaced►──┐ │ │ │ ┌────◄begin at this |
║ old string to be replaced►──┐ │ │ │ ┌────◄begin at this occurrence #║ |
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║ {O, H, and N can be null.} │ │ │ │ │ ┌──◄start position (default=1)║ |
║ {O, H, and N can be null.} │ │ │ │ │ ┌──◄start position (default=1)║ |
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╚═╦════════════════════════════╗ │ │ │ │ │ │ ╔═════════════════════════╦═╝ |
╚═╦════════════════════════════╗ │ │ │ │ │ │ ╔═════════════════════════╦═╝ |
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h=substr(h,p) /*only use this part of H.*/ |
h=substr(h,p) /*only use this part of H.*/ |
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end /*now, proceed as usual. */ |
end /*now, proceed as usual. */ |
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#=0 /*# of changed |
#=0 /*# of changed occurrences*/ |
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do j=1 while # < t /*keep changing, T times. */ |
do j=1 while # < t /*keep changing, T times. */ |
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parse var h y (o) _ +(L) h /*parse the haystack ··· */ |
parse var h y (o) _ +(L) h /*parse the haystack ··· */ |
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$=$ || y /*append the residual txt.*/ |
$=$ || y /*append the residual txt.*/ |
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if j<b then $=$ || o /*append OLD if too soon. */ |
if j<b then $=$ || o /*append OLD if too soon. */ |
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else do /*met the |
else do /*met the occurrence test.*/ |
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$=$ || n /*append the NEW string.*/ |
$=$ || n /*append the NEW string.*/ |
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#=#+1 /*bump |
#=#+1 /*bump occurrence number.*/ |
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end |
end |
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end /*j*/ |
end /*j*/ /*Note: most REXX ··· */ |
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/* |
/* CHANGESTR BIFs only ···*/ |
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return f || $ || h /* |
return f || $ || h /* support three options. */</lang> |
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