plperl arginfo

While we were discussing allowing generic record type arguments to
plperl functions, Tom suggested that we should expose the type
information about the record members to plperl. I think if we do that we
should probably expand it somewhat to all arguments, so that for
non-trigger functions, we'd have $_ARG_INFO while could look something
like this:

{
names => ['arg1', undef, 'arg3' ] , # no name was supplied for arg2
modes => ['in', 'in', 'in' ], # do we support anything other
than IN ?
types => ['integer', 'text', { name => 'somecomposite', fields
=> [ 'field1', 'field2' ], types => ['date', 'numeric' ] } ],
}

Maybe we should also pass in type Oid info, too.

I don't think this would be terribly difficult to do.

thoughts?

cheers

andrew