Hans, sorry I duped you on this message.
----- Original Message ----
> From: Hans Dieter Pearcey <h...@pobox.com>
> To: moose <moose@perl.org>
> Sent: Thursday, September 3, 2009 8:52:02 PM
> Subject: subtyping parameterized types
>
> subtype Foo, as ArrayRef[Str], where { @$_ < 5 };
>
> Foo is now a parameteriz*able* type, not a parameteriz*ed* type; that is,
> in theory (if the MooseX::Types decorators allow it), you can:
>
> has foo_classes => (isa => Foo[ClassName]);
>
> since ClassName is a subtype of Str.
>
> This surprised me, and means that Native::Trait::Array/Hash totally don't work
> with subtypes of parameterized types.
We had a discussion about this a while back when I was adding
parameterization support to MooseX::Types. I think this was a least of
evils, let's punt until we really understand what we want. I
duplicated the behavior for MooseX::Types::Structured, btw, you can
reparamterize a structured type as long as you don't contradict the
existing type. I took a similar approach to the stuff in the repo
under MooseX::Dependent.
As I said, this was the best idea we could come up with without any real use
cases. Seems we have one now :)
>
> I'm poking at this now. Any insight is welcome.
>
> hdp.
