Re: regexp_replace( , , , NULL ) returns null?

Jim Nasby <jnasby(at)enova(dot)com> writes:
> Is there any particular reason for this:
> decibel(at)decina(dot)local=# SELECT regexp_replace( 'a', 'a', 'b', null ) IS NULL;
> ?column?
> ----------
> t
> (1 row)

Yeah: regexp_replace is strict.

> ISTM itd be a lot better if it treated NULL flags the same as ...

In Oracle's universe that probably makes sense, but to me it's not
sensible. Why should "unknown" flags produce a non-unknown result?

I find it hard to envision many use-cases where you wouldn't actually
have the flags as a constant, anyway; they're too fundamental to the
behavior of the function.

regards, tom lane