Re: Experiences with match() subexpressions?

On 10.04.2025 16:04, Kenny McCormack wrote:

In article <vt8bit$2uiq5$1@dont-email.me>,
Janis Papanagnou  <janis_papanagnou+ng@hotmail.com> wrote:
...

I have to admit that I (still) don't really understand how this match third
arg stuff works.

...

I.e., I can never predict what will happen, so I always
just dump out the array and try to reverse-engineer it each time I need to
use it.

...

Above output stuff appears because in 'arr' there's additional elements
about the pattern positions stored.

 
Just to clarify, I wasn't looking for a tutorial (man page regurgitation).
I understand the man page description of match's 3rd arg as well as anyone;

(I didn't mean to offend you. Sorry, if it appeared so. - I just
read you writing "I don't really understand how this [...] works",
and that "it is unpredictable", so I thought some descriptive words
may be useful.)

I just find it that it doesn't do as much in practice as (I think) it
should - and that it is unpredictable (by me, anyway) what it will do (you
have to dump out the array and trial-and-error it to get it to do what you
want).

It is pretty understandable to me, and not the least unpredictable.
(That's why I thought it would be okay to write what I had written
to explain it.) I don't understand what you find to be unpredictable.
But never mind.

It promises more than it delivers.

Yes, probably. Although, according to what's literally documented,
it doesn't promise too much, IMO. 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.

[...]
 
None of which is criticism of the feature; as you say below, it basically
does as much as the underlying regexp library allows it to do.
 
...

I think I'll do the parsing the straightforward two-step way as I did
before the GNU Awk specific functions were available; it's probably
also the clearest way to program that functionality.

 
Probably so.  BTW, it is not really "GNU Awk specific"; lots of languages
have this general capability.

Oh, I was just trying to say that for my programming the standard Awk
functions (as opposed to GNU Awk _specific_ functions) are fine here.
(That should not disdain all the useful GNU Awk extensions existing.)

Janis

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