Re: Regex match not back-referencing in function - Mailing list pgsql-general

Thom Brown <thom@linux.com> writes:
> What am I missing?

I might be more confused than you, but I think you're supposing that
the result of ascii(E'\\1') has something to do with the match that
the surrounding regexp_replace function will find, later on when it
gets executed.  The actual arguments seen by regexp_replace are

regression=# select E'Hello & goodbye ',E'([&])','&#' ||
ascii(E'\\1') || E';\\1';
     ?column?     | ?column? | ?column?
------------------+----------+----------
 Hello & goodbye  | ([&])    | \\1
(1 row)

and given that, the result looks perfectly fine to me.

If there's a bug here, it's that ascii() ignores additional bytes in its
input instead of throwing an error for a string with more than one
character.  But I believe we've discussed that in the past and decided
not to change it.

            regards, tom lane