Re: Spec on pg_cast table/CREATE CAST command

Peter Eisentraut <peter_e@gmx.net> writes:
> Command syntax is
>   CREATE CAST (source AS target) WITH FUNCTION name(arg) [AS ASSIGNMENT]
> in compliance with SQL99 (AS ASSIGNMENT means implicitly invokable).
> Declaration of binary compatible casts:
>   CREATE CAST (source AS target) WITHOUT FUNCTION [AS ASSIGNMENT]

So the idea is to remove proimplicit again?  We could still do that
before 7.3, since no user depends on it yet.  Are you intending a new
system catalog to hold casts?
        regards, tom lane