On Sat, Jul 04, 2009 at 12:31:35AM +0100, Mark Morgan wrote:
> In my case, I'm attempting to ensure that only a single attribute is
> marked as 'asdf' for a given class. The specified attribute would be
> treated specially during constuction
package My::Meta::Attribute::Trait::Highlander;
use Moose::Role;
before attach_to_class => sub {
my ($self, $metaclass) = @_;
my ($existing) = grep {
$_->does(__PACKAGE__)
} $metaclass->get_all_attributes;
die "Can't add another highlander to "
. $metaclass->name
. " (found " . $existing->name . ")"
if $existing;
};
Untested, but you should be able to tweak this if it doesn't work right away.
hdp.
