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