Re: RfD: more powerful "any" types

On Thu, 2009-09-10 at 21:30 +0200, Pavel Stehule wrote:
> 2009/9/10 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>:
> > Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> writes:
> >> 2009/9/10 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>:
> >>> 1. Allow the existing "any" pseudotype as an input argument type for PLs.
> >>> (AFAICS this is simple and painless; about the only question is whether
> >>> we want to keep using the name "any", which because of conflicting with
> >>> a reserved word would always need the double quotes.)
> >
> >> I thing so this is possible - I see only one critical point - you
> >> cannot validate source in validation time.
> >
> > How's it any different from anyelement?
>
> true, if I remember well, there is substitution from anyelement to int?
>
> maybe from this perspective can be good to separate polymorphic types
> to some kinds:
>
> any - really unknown type - there is possible only check on null or
> not null (and maybe some basic operations).
> anytext - any value (substituted to text) in validation time
> anynumeric - any value (substitued to integer) in validation time.

I think that way madness lies.

then we should have anyXXX types for almost any subsets of types

anytime , anygeom, anypointpair, anymorethantwopaintgeom, etc...

better have a (possibility of) validation at compile time and
validation/error-throwing at runtime - the latter is needed anyway.

Unless we are going to implement CHECK constraints for function
arguments and then use constraint exclusion for selecting the correct
function ;)

> regards
> Pavel Stehule
>
> >
> > regards, tom lane
> >
>