Re: find attributes type_constraints

Christoph,

On May 6, 2007, at 5:42 PM, Ch Lamprecht wrote:
> 'ArrayRef' is in the name attribute of the TypeConstraint, but I  
> don't see a way to get the classname 'TkObjectsView' back out of  
> the second type_constraint object.

Yes, because Moose has never encountered TkObjectsView before, it  
cannot tell for sure what it is, so as a compromise, it will assume  
it is an object and give you the ANON type constraint which will do  
the right thing for that assumption. The reason it does not make an  
officially named type constraint is that Moose cannot be sure that it  
*should* do that, and that you won't try to make a type constraint  
using that name later on, which has an entirely different meaning.

> Will I have to explicitly create a 'Moose::Meta::TypeConstraint'  
> for every class
> I want to use in an attribute to make this work?

That is one way, but an easier way is to do this:

$attr->_isa_metadata;

It will give you back the original string from the 'isa' option.  
There is also a &_does_metadata and &_is_metadata as well.

This should be considered a "semi-private" method, which is to say it  
is not part of the core API, but can be used outside of the class and  
will not likely change. It is there specifically for introspective  
uses like yours and is already (ab)used heavily in the Reaction code  
base IIRC.

- Stevan