On Wed, Jun 03, 2009 at 06:06:20PM +0100, Mark Morgan wrote: > This behaviour has bitten me a few times too, taking quite a bit of > time to find the cause of. Is there any intention to give a default > 'is' value, or raise a warning, if no access parameters are given?
No. For example, you might want this: has things => ( metaclass => 'Collection::Array', isa => ArrayRef[Thing], provides => { elements => 'things', }, ); It should be easy to write an attribute metaclass role that provides a default. hdp.