Greetings. Apologies if this has been asked before or is easily found by searching (I've tried, honest).

I'm using Moose and trying to apply a trait to an attribute which automatically adds a method into the containing class. I've done this successfully but I'm thinking there's a better way here, and I'd appreciate any feedback provided.

Thanks in advance.

#!/usr/local/bin/perl
use strict;
use warnings;
package Me::Trait::M;
use Moose::Role;

has mything => ( isa => 'Maybe[Bool]', is => 'rw', default => 0 );

no Moose::Role;

package Moose::Meta::Attribute::Custom::Trait::M;
sub register_implementation { 'Me::Trait::M'; }

package Me;
use Moose;

has myattr_yes => ( isa => 'Str', is => 'ro',
  traits => [qw/M/],
  default => 'this_is_yes',
  mything => 1,
);

has myattr_no => ( isa => 'Str', is => 'ro',
  default => 'this_is_no',
);

sub BUILD {
  my $self = shift;
  my $meta = $self->meta;
  my @attr = $meta->get_all_attributes();
  foreach my $at (@attr) {
    if ($at->does('Me::Trait::M')) {
      my $closure = $at->name;
      my $coderef = sub {  
        my $self = shift;
        print $self->$closure()."\n";
      };
      $meta->add_method( 'print_' . $closure => $coderef);
    }
  }
}


no Moose;
package main;

my $f = Me->new();
$f->print_myattr_yes();

[download]

UPDATE: Perusing the way that the deprecated MooseX::AttributeHelpers worked led me to understand Tobyink's comment below. Here is a cleaner solution, involving just the role:

package Me::Trait::M;
use Moose::Role;

has mything => ( isa => 'Maybe[Bool]', is => 'rw', default => 0 );

after 'install_accessors' => sub {
  my $self = shift;
  my $realclass = $self->associated_class();
  my $closure = $self->name;
  my $coderef = sub {  
    my $self = shift;
    print $self->$closure()."\n";
  };
  $realclass->add_method( 'print_' . $closure => $coderef );
};

no Moose::Role;

[download]

Thanks again for the insight!

UPDATE2: Made the idea a bit clearer, no need to loop the attributes since $self is apparently an attribute class

In reply to Moose: Adding methods to a class via attribute traits by Nasrudin

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