Checking regex pattern validity

[David Garamond]

Is there a function like IS_VALID_REGEX( ) to check whether a pattern is
valid (i.e. it compiles)? I'm storing a list of regex patterns in a
table. It would be nice to be able to add a CHECK constraint to ensure
that all the regexes are valid.

If there isn't any, can I suggest Postgres add one? Although I know this
can probably be done in plpgsql using exception handling, or done in
plperl or plruby.

--
dave


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[Tom Lane]

Re: Checking regex pattern validity

David Garamond <lists@zara.6.i sreserved.com> writes:[color=blue]
> Is there a function like IS_VALID_REGEX( ) to check whether a pattern is
> valid (i.e. it compiles)? I'm storing a list of regex patterns in a
> table. It would be nice to be able to add a CHECK constraint to ensure
> that all the regexes are valid.[/color]

... CHECK (('' ~ pattern) IS NOT NULL) ...

regards, tom lane

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[David Garamond]

Re: Checking regex pattern validity

Tom Lane wrote:[color=blue]
> David Garamond <lists@zara.6.i sreserved.com> writes:
>[color=green]
>>Is there a function like IS_VALID_REGEX( ) to check whether a pattern is
>>valid (i.e. it compiles)? I'm storing a list of regex patterns in a
>>table. It would be nice to be able to add a CHECK constraint to ensure
>>that all the regexes are valid.[/color]
>
> ... CHECK (('' ~ pattern) IS NOT NULL) ...[/color]

Not exactly what I wanted, but close enough. Thanks!

However, what if only want to accept invalid regex patterns? Or what if
invalid pattern should be converted to NULL automatically? I'd still
vote for a function...

--
dave

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