CHANGESTR.REX: Difference between revisions
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m (→the CHANGESTR source: changed a comment to reflect its IF statement.) |
m (→the CHANGESTR source: changed some comments (to align better for perusing).) |
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↓ ↓ ↓ ↓ ↓ ↓ */ |
↓ ↓ ↓ ↓ ↓ ↓ */ |
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changestr: parse arg o,h,n,t,b,p, |
changestr: parse arg o,h,n,t,b,p, ,$ f /* ◄────────────────────┐*/ |
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/*T, B, P are optional ►─┘*/ |
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t=word(t 999999999, 1) /*maybe use the default? */ |
t=word(t 999999999, 1) /*maybe use the default? */ |
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b=word(b 1 , 1) /* " " " " */ |
b=word(b 1 , 1) /* " " " " */ |
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if \datatype(t, 'W') then signal syntax /*4th arg not an integer. */ |
if \datatype(t, 'W') then signal syntax /*4th arg not an integer. */ |
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if \datatype(b, 'W') then signal syntax /*5th " " " " */ |
if \datatype(b, 'W') then signal syntax /*5th " " " " */ |
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if \datatype(p, 'W') then signal syntax /*6th |
if \datatype(p, 'W') then signal syntax /*6th " " " " */ |
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if t<0 then signal syntax /*4th |
if t<0 then signal syntax /*4th " " non-negative.*/ |
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if b<1 then signal syntax /*5th |
if b<1 then signal syntax /*5th " " positive. */ |
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if p<1 then signal syntax /*6th " " " */ |
if p<1 then signal syntax /*6th " " " */ |
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L=length(o) /*length of OLD string. */ |
L=length(o) /*length of OLD string. */ |
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if L==0 & t\=0 then return n || h /*changing a null char? |
if L==0 & t\=0 then return n || h /*changing a [null] char? */ |
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/* [↓] check for position*/ |
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if p\=1 then do /*P¬=1? Then ajust F & H.*/ |
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f=left(h, min(p-1, length(h))) /*keep first part intact. */ |
f=left(h, min(p-1, length(h))) /*keep first part intact. */ |
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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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if _=='' then return f || $ || y /*no more left, return. */ |
if _=='' then return f || $ || y /*no more left, return. */ |
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$=$ || y /*append the residual txt.*/ |
$=$ || y /*append the residual txt.*/ |
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/* [↓] check if too soon.*/ |
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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 occurrence test.*/ |
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 /* [↑] append new string.*/ |
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end /*j*/ /*Note: most REXX ··· */ |
end /*j*/ /*Note: most REXX ··· */ |
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/* CHANGESTR BIFs only ···*/ |
/* CHANGESTR BIFs only ···*/ |
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