use strict;
use warnings;
-use Carp 'confess';
+use Carp 'confess';
+use Scalar::Util 'blessed';
+use Try::Tiny;
-our $VERSION = '0.01';
+our $VERSION = '1.09';
+$VERSION = eval $VERSION;
+our $AUTHORITY = 'cpan:STEVAN';
use Class::MOP;
sub import {
- shift;
- my $metaclass = shift || 'Class::MOP::Class';
- my %options = @_;
- my $package = caller();
-
- ($metaclass->isa('Class::MOP::Class'))
- || confess 'The metaclass must be derived from Class::MOP::Class';
-
- # create a meta object so we can install &meta
- my $meta = $metaclass->initialize($package => %options);
- $meta->add_method('meta' => sub {
- # we must re-initialize so that it
- # works as expected in subclasses,
- # since metaclass instances are
- # singletons, this is not really a
- # big deal anyway.
- $metaclass->initialize($_[0] => %options)
- });
-}
-
-=pod
-
-NOTES
-
-Okay, the metaclass constraint issue is a bit of a PITA.
-
-Especially in the context of MI, where we end up with an
-explosion of metaclasses.
-
-SOOOO
-
-Instead of auto-composing metaclasses using inheritance
-(which is problematic at best, and totally wrong at worst,
-especially in the light of methods of Class::MOP::Class
-which are overridden by subclasses (try to figure out how
-LazyClass and InsideOutClass could be composed, it is not
-even possible)) we use a trait model.
-
-It will be similar to Class::Trait, except that there is
-no such thing as a trait, a class isa trait and a trait
-isa class, more like Scala really.
+ my ( $class, @args ) = @_;
-This way we get several benefits:
+ unshift @args, "metaclass" if @args % 2 == 1;
+ my %options = @args;
-1) Classes can be composed like traits, and it Just Works.
+ my $metaclass = delete $options{metaclass};
-2) Metaclasses can be composed this way too :)
+ unless ( defined $metaclass ) {
+ $metaclass = "Class::MOP::Class";
+ } else {
+ Class::MOP::load_class($metaclass);
+ }
-3) When solving the metaclass constraint, we create an
- anon-metaclass, and compose the parent's metaclasses
- into it. This allows for conflict checking trait-style
- which should inform us of any issues right away.
-
-Misc. Details:
+ ($metaclass->isa('Class::MOP::Class'))
+ || confess "The metaclass ($metaclass) must be derived from Class::MOP::Class";
-Class metaclasses must be composed, but so must any
-associated Attribute and Method metaclasses. However, this
-is not always relevant since I should be able to create a
-class which has lazy attributes, and then create a subclass
-of that class whose attributes are not lazy.
+ # make sure the custom metaclasses get loaded
+ foreach my $key (grep { /_(?:meta)?class$/ } keys %options) {
+ unless ( ref( my $class = $options{$key} ) ) {
+ Class::MOP::load_class($class)
+ }
+ }
+ my $package = caller();
-=cut
+ # create a meta object so we can install &meta
+ my $meta = $metaclass->initialize($package => %options);
+ my $should_install = !delete $options{no_meta};
+ $meta->add_method('meta' => sub {
+ # we must re-initialize so that it
+ # works as expected in subclasses,
+ # since metaclass instances are
+ # singletons, this is not really a
+ # big deal anyway.
+ if (Class::MOP::DEBUG_NO_META()) {
+ my ($self) = @_;
+ if (my $meta = try { $self->SUPER::meta }) {
+ return $meta if $meta->isa('Class::MOP::Class');
+ }
+ confess "'meta' method called by MOP internals"
+ if caller =~ /Class::MOP|metaclass/;
+ }
+ $metaclass->initialize((blessed($_[0]) || $_[0]) => %options)
+ }) if $should_install;
+}
1;
=head1 NAME
-metaclass - a pragma for installing using Class::MOP metaclasses
+metaclass - a pragma for installing and using Class::MOP metaclasses
=head1 SYNOPSIS
+ package MyClass;
+
+ # use Class::MOP::Class
+ use metaclass;
+
+ # ... or use a custom metaclass
use metaclass 'MyMetaClass';
-
+
+ # ... or use a custom metaclass
+ # and custom attribute and method
+ # metaclasses
use metaclass 'MyMetaClass' => (
- ':attribute_metaclass' => 'MyAttributeMetaClass',
- ':method_metaclass' => 'MyMethodMetaClass',
+ 'attribute_metaclass' => 'MyAttributeMetaClass',
+ 'method_metaclass' => 'MyMethodMetaClass',
);
+ # ... or just specify custom attribute
+ # and method classes, and Class::MOP::Class
+ # is the assumed metaclass
+ use metaclass (
+ 'attribute_metaclass' => 'MyAttributeMetaClass',
+ 'method_metaclass' => 'MyMethodMetaClass',
+ );
+
+ # if we'd rather not install a 'meta' method, we can do this
+ use metaclass no_meta => 1;
+
=head1 DESCRIPTION
-This is a pragma to make it easier to use a specific metaclass
-and it's
+This is a pragma to make it easier to use a specific metaclass
+and a set of custom attribute and method metaclasses. It also
+installs a C<meta> method to your class as well, if the
+C<no_meta> option is not specified.
-=head1 AUTHOR
+=head1 AUTHORS
Stevan Little E<lt>stevan@iinteractive.comE<gt>
=head1 COPYRIGHT AND LICENSE
-Copyright 2006 by Infinity Interactive, Inc.
+Copyright 2006-2010 by Infinity Interactive, Inc.
L<http://www.iinteractive.com>
This library is free software; you can redistribute it and/or modify
-it under the same terms as Perl itself.
+it under the same terms as Perl itself.
-=cut
\ No newline at end of file
+=cut