Tom Lane wrote:
> The null Datum itself obviously doesn't carry that info, but the
> expression tree does, and there are provisions for letting functions
> retrieve that info --- see get_fn_expr_rettype and get_fn_expr_argtype.
Hmm. I vaguely remember that there was some feeling that the PLs
wouldn't always fill out the FmgrInfo struct, but perhaps that was just
the case with I/O functions.
>> ... could we
>> have a special rule that would look for e.g. a regtype as the first
>> parameter if the return type is generic and there are no generic parameters?
>
> I thought about that too but don't like it much. The problem is mainly
> that it can only work for a constant regtype parameter.
OK, I give up. :) Why?
Thanks
Tom