Re: [Bug-apl] Not a bug, need help coding search&replace on a vector

[Juergen Sauermann]

Hi, I believe regular expressions would be a useful and reasonable thing and I would not object to making it a ⎕-function. I can provide the framework for the ⎕-part of it (class definition, parser etc) if somebody wants to fill in the rest. I would need to know its name, and how it is called (monadic, dyadic, axis, function argument(s) etc). Please also provide a testcase file to check if (and demonstrate how) it works. /// Jürgen On 06/22/2016 05:41 AM, Elias Mårtenson wrote: Sure, that shouldn't be a problem at all. Regards, Elias On 22 June 2016 at 11:10, Christian Robert <christian.rob...@polymtl.ca> wrote: Oh yes, would be nice. (pcre would be as nice as regex, may be more) make it a ⎕regex or ⎕pcre so, no need to load a specific .so file or )lib to use it ;-) Ideal would be to be able to not only scan but be able to compile a pcre, find patterns, search & replace ... I am dreaming, but still awake ... Xtian. On 2016-06-21 22:39, Elias Mårtenson wrote: Would anyone be interested if I actually implemented support regex by calling into the C library? I'm envisioning something like this: *      "^([a-z]+):([0-9]+)$" regex∆scan "foo:123"* ┏→━━━━━━━━━━┓ ┃"foo" "123"┃ ┗∊━━━━━━━━━━┛ Regards, Elias On 22 June 2016 at 10:35, Xiao-Yong Jin <jinxiaoy...@gmail.com <mailto:jinxiaoy...@gmail.com>> wrote:     At some point I really wanted to implement the simplest editor, namely ed (it would be much better than any APL system has offered), in APL, but I never finished the regex part.  Perhaps it would be a nice exercise for someone who’s interested in learning APL to actually implement some of the most used Unix command line utilities.     > On Jun 21, 2016, at 8:53 PM, Christian Robert <christian.rob...@polymtl.ca <mailto:christian.rob...@polymtl.ca>> wrote:     >     > Hi,     >     > A more general purpose search&replace (some bug fixed), take (2), was "snr".     >     >     >     >      )sic     >      )erase replace     >      ∇z←s replace p;fr;to;P;i;⎕io     > ⍝ -------------     > →(2≤≡s)/ForEach     > →(2≤⍴⍴s)/Matrix     > →Vector     > ⍝ -------------     > ForEach: z←{⍵ replace p}¨s ◊ →0     > Matrix: z←⊃ {⍵ replace p}¨ ⊂[2]s ◊ →0     > ⍝ -------------     > Vector: p←,¨p ◊ z←s←,s ⋄ ⎕io←1     > Loop:→((⍴p)<2)/0     > (fr to)←2↑p ◊ p←2↓p     > P←¯1↓∧/[1](¯1+⍳⍴fr)⌽fr∘.=z,⎕ucs 1     > i←0     > Sanitize: i←i+1     > →(i>(⍴P)-⍴fr)/Substitute     > →(0=P[i])/Sanitize     > ((⊂ i+¯1+⍳⍴fr)⌷P)←(⍴fr)↑1     > →Sanitize     > Substitute: P←⌽(P/⍳⍴P)     > ⊣ {z←((¯1+⍵)↑z),to,(¯1+⍵+⍴fr)↓z}¨P     > →Loop     > ∇     >     > It should be vector, matrix and embedded objects "aware" (as long as it is all text)     >     > Syntax:     >     >  source replace "this" "by_that" "this" "by_that" [...]  (eg: pairs of "from" and "to")     >     > Examples:     >     >      (⎕cr 'replace') replace 'replace' 'snr' 'ForEach' "Each" "Substitute" "Subst" "Sanitize" "Sane"     > z←s snr p;fr;to;P;i;⎕io     > ⍝ -------------     > →(2≤≡s)/Each     > →(2≤⍴⍴s)/Matrix     > →Vector     > ⍝ -------------     > Each: z←{⍵ snr p}¨s ◊ →0     > Matrix: z←⊃ {⍵ snr p}¨ ⊂[2]s ◊ →0     > ⍝ -------------     > Vector: p←,¨p ◊ z←s←,s ⋄ ⎕io←1     > Loop:→((⍴p)<2)/0     > (fr to)←2↑p ◊ p←2↓p     > P←¯1↓∧/[1](¯1+⍳⍴fr)⌽fr∘.=z,⎕ucs 1     > i←0     > Sane: i←i+1     > →(i>(⍴P)-⍴fr)/Subst     > →(0=P[i])/Sane     > ((⊂ i+¯1+⍳⍴fr)⌷P)←(⍴fr)↑1     > →Sane     > Subst: P←⌽(P/⍳⍴P)     > ⊣ {z←((¯1+⍵)↑z),to,(¯1+⍵+⍴fr)↓z}¨P     > →Loop     >     >     > You can even try "⎕fx" the result if it looks like Ok. (ps: always check the result before committing)     >     > Substitutions are done in pair sequence for each /vector/matrix/embedded obj.     >     > So replace order is *very* important.     >     > It must still have some bugs, report them to me, with examples if so. Will do my best but no promises.     >     > Purpose: well, not sure, it was an exercise. I used it on itself to finally rename the function and change some variables/labels names.     >     >     > Features: would be fun to pass parameters to each of the /from/to/ like maximum number of substitutions to do per line ...     >          whole words only (taking apl characters as blanks) ... so variable "s" won't match last character of variable "pairs"     >          ... no limits     >     >     > Xtian.     >     >     > On 2016-06-21 12:27, Juergen Sauermann wrote:     >> Hi Xtian,     >>     >> how about this:     >>     >> *      **s←"444This4is4a4444test44with44444lot4of4blanks4444at4beginning4and444end444444"**     >>      from←"444"**     >> **      to←"5"**     >> **     >> **      ↑⍎')HOST echo "',s,'" | sed s/',from,'/',to,'/g'**     >> **5This4is4a54test44with544lot4of4blanks54at4beginning4and5end55**     >> **  **     >> *I have replaced the *^* in your example because it (and some other characters) have a special meaning in     >> regular expressions. But the special characters can be easily quoted in APL if needed, for example:     >>     >> *      s←"^^^This^is^a^^^^test^^with^^^^^lot^of^blanks^^^^at^beginning^and^^^end^^^^^^" **     >> **      ((s='^')/s)←⊂'\^'**     >> **      ⊃,/s**     >> **\^\^\^This\^is\^a\^\^\^\^test\^\^with\^\^\^\^\^lot\^of\^blanks\^\^\^\^at\^beginning\^and\^\^\^end\^\^\^\^\^\^**     >> *     >> /// Jürgen     >>     >>     >> On 06/21/2016 05:12 AM, Christian Robert wrote:     >>> Hi, it's not a bug but a request for help,     >>>     >>>     >>> suppose s="^^^This^is^a^^^^test^^with^^^^^lot^of^blanks^^^^at^beginning^and^^^end^^^^^^"     >>> suppose from="^^^"     >>> suppose to="^"     >>>     >>> I need a function who can replace ("^^^" to "^"), or ("^" to "^^^^^^^^") or ("" to "blabla" with limits of source size)  ie: without being lost in infinite loop.     >>>     >>>     >>>     >>> "s" is a character vector, "from" is a character vector, and "to" is a character vector,     >>> both "s", "from" and "to" can be "".     >>>     >>>     >>>     >>> I'm pretty sure this idiom already exist.     >>>     >>> if you can help me, please do.     >>>     >>> Xtian.     >>>     >>>     >>>     >>>     >>>     >>>     >>