Re: change regexp_substr first argument make tests more easier to understand.

On Thu, Dec 28, 2023 at 12:13 AM jian he <jian.universality@gmail.com> wrote:
>
> hi.
> https://git.postgresql.org/cgit/postgresql.git/tree/src/test/regress/expected/strings.out#n928
>
> SELECT regexp_substr('abcabcabc', 'a.c');
> SELECT regexp_substr('abcabcabc', 'a.c', 2);
> SELECT regexp_substr('abcabcabc', 'a.c', 1, 3);
> SELECT regexp_substr('abcabcabc', 'a.c', 1, 4) IS NULL AS t;
> SELECT regexp_substr('abcabcabc', 'A.C', 1, 2, 'i');
>
> they all return 'abc', there are 3 'abc ' in  string 'abcabcabc'
> except IS NULL query.
> maybe we can change regexp_substr first argument from "abcabcabc" to
> "abcaXcaYc".
> so the result would be more easier to understand.

anyway here is the minor patch to  change string from "abcabcabc" to
"abcaXcaYc".