Using attributes for 'requires'

G'day Moosers,

I'm currently working on some quick lightning talks demonstrating Moose and
why it's useful.  One of the examples I'm using for roles looks like this:

	package SunSmart;

	use Moose::Role;
	use Weather::Google;

	use constant HOT => 28;		# Deg C.

	requires 'go_outside';
	requires 'location';

	before 'go_outside' => sub {
	    my ($self) = @_;

	    my $weather = Weather::Google->new(
	        $self->location
	    );

	   if ($weather->current->{temp_c} > HOT) {
	      print "Don't forget your hat!\n";
	   }
	}

In short, if something has a location, and the ability to go_outside, then
we can give it the SunSmart role, and it won't forget its hat if it's too hot.

Unfortunately for me, `location` is an attribute on practically all of my
classes, and Moose doesn't seem to like having an attribute to satisfy a
'requires':

	'SunSmart' requires the method 'location' to be implemented by
	'Person::Social'but the method is only an attribute accessor at
	/usr/lib/perl5/site_perl/5.8/Moose/Meta/Role/Application.pm line 59

This makes me sad, since I really *do* require a location method, but it's
absolutely fine if it's an attribute.

I know there have been some discussions about this in the past, with the
possibility of a 'requires_attr' or similar keyword, although to the best of
my knowledge this is not yet implemented.

In the meantime, is there any easy[1] way to tell Moose that attributes are
just fine to satisify 'requires' dependencies?

Many thanks,

	Paul

[1] Since I'm writing short talks for mixed audiences, I can't show anything
too scary.  Sure, I'm willing to dig around in the guts of all sorts of
things, but I'm trying to dispel the myth that as a regular Perl programmer
you should have to.

-- 
Paul Fenwick <[email protected]> | http://perltraining.com.au/
Director of Training                   | Ph:  +61 3 9354 6001
Perl Training Australia                | Fax: +61 3 9354 2681