Re-added to open items:

        Fix SIMILAR TO to be ANSI compliant or remove it (Peter, Tom)


Tom Lane wrote:
> "Marc G. Fournier" <[EMAIL PROTECTED]> writes:
> > I'm in agreement with Thomas here ... unless a problem has been defined a
> > bit more specifically then 'it isn't posix compliant', it shouldn't be
> > considered an open item ... please remove?
> A quick review of SQL99 says that their notion of SIMILAR TO patterns
> is an unholy witches' brew: it does *both* common-or-garden regexp
> expressions and LIKE patterns.  Specifically, I see these
> metacharacters:
>       |               OR  (regexp-ish)
>       *               repeat 0 or more times  (regexp-ish)
>       +               repeat 1 or more times  (regexp-ish)
>       %               match any character sequence  (like LIKE)
>       _               match any one character  (like LIKE)
>       [...]           almost-but-not-quite-regexp-ish character class
>       (...)           grouping  (regexp-ish)
> plus a just-like-LIKE treatment of a selectable escape character.
> But the most important variation from common regex practice is that
> (if I'm reading the spec correctly) the pattern must match to the
> entire target string --- ie, it's effectively both left- and right-
> anchored.  This is like LIKE patterns but utterly unlike common regexp
> usage.
> I could live with the fact that our regexp patterns don't implement all
> of the spec-mandated metacharacters.  But I do not think we can ignore
> the difference in anchoring behavior.  This is not a subset of the spec
> behavior, it is just plain wrong.
> I vote with Peter: we fix this or we disable it before 7.3 release.
> It is not anywhere near spec compliant, and we will be doing no one
> a favor by releasing it in the current state.
>                       regards, tom lane
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