Re: RFC 218 (v1) C<my Dog $spot> is just an assertion

Nathan Torkington wrote:
> 
> Yes!  I mentioned the hypothetical
>   use strict 'types';
> which would require all variables assigned to/from an object, and
> all variables upon which method calls are made, to be typed like
> this.  Then the compiler can:
>  (a) optimize
>  (b) check at compile-time

Hate to add a "me too", but I think this is a great idea. Nat needs to
be able to torture himself in whatever sick C-type ways he desires. ;-)
;-)
 
Seriously, though, this adds lots of potential benefits.

> Polymorphic
> types also becomes a problem: how to say that it's okay for a variable
> to hold a Dog *or* a Cat, because we know that both of them have a
> "pet()" method?

Seems in order to satisfy this you'd have to have a common ancestor,
Pet, which Dog and Cat inherited:

   my Pet $foofoo;      # Can be Dog, Cat, or anything inherited

And if you didn't want inherited classes to count, you could specify
that as an attribute:

   my Pet $foofoo : onlybase;    # Must be a Pet, not Cat/Dog

Or ":only", ":nochildren", ":justme", or any other similar word...

-Nate