Re: [DOCS] can't be both non-capturing and still capture - Mailing list pgsql-docs

srn@coolheads.com writes:
> Here, the whole regexp is non-capturing, right, so how can the result be
> reported as shown?

No, the outer parens are non-capturing, but the ones inside them still
are capturing parens.

Perhaps it would clarify matters if you tried it with plain outer parens:

=# SELECT regexp_matches('abc01234xyz', '((.*?)(\d+)(.*)){1,1}');
       regexp_matches
-----------------------------
 {abc01234xyz,abc,01234,xyz}
(1 row)

In this case we get a report from each of the four sets of capturing
parens.  Or another example:

=# SELECT regexp_matches('abc01234xyz', '((?:.*?)(\d+)(.*)){1,1}');
     regexp_matches
-------------------------
 {abc01234xyz,01234,xyz}
(1 row)

Outer parens capture, first inner set don't, other two inner sets do.

            regards, tom lane