use MooseX::Declare;
role My::DirOption {
	requires '_build_rootdir';
	
	has rootdir => (
		isa => 'Str',
		is => 'rw',
		lazy => 1,
		builder => '_build_rootdir',
	);
}
# Make meta attribute trait known to Moose under a short name 
class Moose::Meta::Attribute::Custom::Trait::DirOption {
	sub register_implementation {'My::DirOption'}
}

class My::Config {
	use strict;
	use warnings;

	has testdir => (
		traits => ['DirOption'],
		isa => 'Str',
		is => 'rw',
	);

	## This is the wrong place for the builder!
	method _build_rootdir() {
		return '/home/paulatreides';
	}
}
1;