From: Massimo Dal Zotto <dz@cs.unitn.it>
Date: Mon, 6 May 1996 01:03:37 +0200 (MET DST)
Subject: [PG95]: new operators for arrays

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Hi,

I have written an extension to Postgres95 which allows to use qualification
clauses based on the values of single elements of arrays.
For example I can now select rows having some or all element of an array
attribute equal to a given value or matching a regular expression:

select * from t where t.foo *= 'bar';
select * from t where t.foo **~ '^ba[rz]';

The scheme is quite general, each operator which operates on a base type can
be iterated over the elements of an array. It seem to work well but defining
each new operators requires writing a different C function. Furthermore in
each function there are two hardcoded OIDs which reference a base type and
a procedure. Not very portable. Can anyone suggest a better and more portable
way to do it ?  Do you think this could be a useful feature for next release ?
Here is my code, it can be compiled and loaded as a dynamic module without
need to recompile the backend. I have defined only the few operators I needed,
the list can be extended. Feddback is welcome.