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From: Janis Papanagnou <janis_papanagnou+ng@hotmail.com>
Newsgroups: comp.lang.awk
Subject: Re: Experiences with match() subexpressions?
Date: Fri, 18 Apr 2025 14:24:24 +0200
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On 18.04.2025 12:03, Manuel Collado wrote:
> El 11/4/25 a las 9:10, Janis Papanagnou escribió:
>> On 11.04.2025 08:33, Aharon Robbins wrote:
>>> In article <vt9dre$3t3po$1@dont-email.me>,
>>> Janis Papanagnou  <janis_papanagnou+ng@hotmail.com> wrote:
>>>> The feature can be very useful,
>>>> but not for the case I was looking for. - Actually, it could have
>>>> provided the functionality I was seeking, but since GNU Awk relies
>>>> on the GNU regexp functions as they are implemented I cannot expect
>>>> that any provided features gets extended by Awk. - If GNU Awk would
>>>> have an own RE implementation then we could think about using, e.g.,
>>>> another array dimension to store the (now only temporary existing,
>>>> and generally unavailable) subexpressions.
>>>
>>> Actually, this is not so trivial.  The data structures at the C level
>>> as mandated by POSIX are one dimensional; the submatches in parentheses
>>> are counted from left to right. There's no way to represent the
>>> subexpressions that are under control of interval expressions, which
>>> would essentially require a two-dimensional data structure.
>>
>> Yes, that's why I had thought about a 2-dimensional array [on GNU
>> Awk level] so that arr[n][i] for i=1..z would contain the patterns.
>> This is what I actually tried with GNU Awk (before I had asked you)
>> to see whether there's some undocumented feature.
> 
> A 2-dimensional array is not strictly necessary. It could be possible to
> keep the one dimensional array interface and use the same trick for
> multidimensional arrays indices in Posix AWK. I.e., return a list of
> matched values delimited by SUBSEP.

Yes, of course. - My suggestion for using a 2-dimensional array was
suggested only because it's IMO simpler to process and access. And
given that the considered potentially new functionality would have
been non-standard would not hinder that also the match() function
(with the new logic) could use GNU Awk's non-standard 2-dimensional
arrays.

Janis