This seems like it'd be useful. Anyone else have thoughts on it? On May 31, 2010, at 4:09 AM, Daniele Varrazzo wrote:
> Hello, > > I'd like to contribute a "regexp_match()" function as discussed in bug > #5469 [1] The aim is to overcome the limitation outlined in the thread > above <http://archives.postgresql.org/pgsql-bugs/2010-05/msg00227.php>. > > PostgreSQL currently offers the function regexp_matches(), a SRF > (which, unless invoked with the 'g' flag, returns at most one result). > An user interested in the "nonglob" behaviour, i.e. expecting at most > 1 match group, has to adopt special care to avoid records to be > dropped from the target list in case no match is found. Being this a > rather common use case, I'd like to provide a function with a less > astonishing behaviour, i.e. returning a text[] instead of a set of > text[] and returning NULL in case no match is found (the 'g' flag > wouldn't be supported). > > The proposed name is regexp_match(), to underline the semantics very > similar to regexp_matches() but returning a single value as result. > While the symmetry between the names is a pro, an excessive similarity > may result confusing, so I wouldn't be surprised if a better name is > found. The implementation of the function is very simple, given the > infrastructure already available for the other regexp-related > functions. I've actually already implemented it (mostly to check how > easy or hard it would have been: I had never written a C procedure for > PG before): a preliminary patch is attached. > > If the idea is accepted I will submit a complete patch including > documentation and tests. > > Best regards, > > > -- Daniele > <regexp_match.patch> > -- > Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers -- Jim C. Nasby, Database Architect j...@nasby.net 512.569.9461 (cell) http://jim.nasby.net -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
