I wrote:
> * There are a whole bunch of "shell" operators created; try
> select oid::regoperator from pg_operator where oprcode = 0;
> after loading isn.
Actually, the problem with this module is not that it's got too few
operators, but that it's got too many. Trying to have the cross-product
of all possible comparison operators for eight nominally different types
is not very sane.
If we were to make the casts to ean13 be IMPLICIT instead of assignment,
then we could have one set of comparison operators and one opclass for
ean13, and let the restricted types rely on those implicitly. Is there
a good reason to disallow the implicit promotion?
regards, tom lane