defining my own parameterized types

I would like to add my own parameterized type e.g. I would like to be able
to create types like:

 

            SzStr[32]

 

Which would allow me to specify the maximum size of a string that an
attribute can have and will validate the size of the data I'm storing in the
attribute

 

Or to specify that an attribute is a secondary key in some DB like:

 

            DBKey[User]

 

Where User is a Moose class that provides an in memory version of a DB
record and the attribute would be a weak reference to such an object

 

Is this currently possible? I looked at the docs for things like:

 

 
http://search.cpan.org/dist/Moose/lib/Moose/Meta/TypeConstraint/Parameterize
d.pm

 

but that has:

 


 
<http://search.cpan.org/dist/Moose/lib/Moose/Meta/TypeConstraint/Parameteriz
ed.pm#___top> METHODS Description: ^


This class is intentionally not documented because the API is confusing and
needs some work.

 

I would appreciate any pointers to examples or docs

Thanks in advance

Mark Wood-Patrick