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#
# This file is part of MooseX-AbstractMethod
#
# This software is Copyright (c) 2011 by Chris Weyl.
#
# This is free software, licensed under:
#
# The GNU Lesser General Public License, Version 2.1, February 1999
#
package MooseX::AbstractMethod;
{
$MooseX::AbstractMethod::VERSION = '0.004';
}
# ABSTRACT: Declare methods requirements that must be satisfied
use Moose 0.94 ();
use namespace::autoclean;
use Moose::Exporter;
use Moose::Util::MetaRole;
# debugging...
#use Smart::Comments;
{
package MooseX::AbstractMethod::Trait::Class;
{
$MooseX::AbstractMethod::Trait::Class::VERSION = '0.004';
}
use Moose::Role;
use namespace::autoclean;
use Moose::Util qw{ does_role english_list };
sub abstract_method_metaclass {
my $self = shift @_;
return Moose::Meta::Class
->create_anon_class(
# XXX should this just be Moose::Meta::Method as the superclass??
superclasses => [ $self->method_metaclass ],
roles => [ 'MooseX::AbstractMethod::Trait::Method' ],
cache => 1,
)
->name
;
}
sub add_abstract_method {
my ($self, @names) = @_;
my $abstract_meta = $self->abstract_method_metaclass;
for my $name (@names) {
my $method = $abstract_meta->wrap(
sub { Moose->throw_error("Method $name is not implemented!") },
name => $name,
package_name => $self->name,
);
$self->add_method($name => $method);
}
return;
}
# blow up if we're being asked to become immutable, we're a subclasss,
# and we don't implement an abstract method
before make_immutable => sub {
my $self = shift @_;
my @abstract_methods = sort
map { $_->name . ' (from ' . $_->original_package_name . ')' }
grep { $_->original_package_name ne $self->name }
grep { does_role($_, 'MooseX::AbstractMethod::Trait::Method') }
$self->get_all_methods
;
Moose->throw_error(
'These abstract methods have not been implemented in '
. $self->name . ': '
. english_list(@abstract_methods)
) if @abstract_methods;
return;
};
}
{
package MooseX::AbstractMethod::Trait::Method;
{
$MooseX::AbstractMethod::Trait::Method::VERSION = '0.004';
}
use Moose::Role;
use namespace::autoclean;
# well, hello there handsome :)
}
sub abstract { _abstract(@_) }
sub requires { _abstract(@_) }
sub _abstract {
### meta isa: ref $_[0]
return shift->add_abstract_method(@_)
unless $_[0]->isa('Moose::Meta::Role');
goto \&Moose::Role::requires;
}
Moose::Exporter->setup_import_methods(
with_meta => [ qw{ abstract requires } ],
trait_aliases => [
[ 'MooseX::AbstractMethod::Trait::Method' => 'AbstractMethod' ],
],
class_metaroles => {
class => [ 'MooseX::AbstractMethod::Trait::Class' ],
},
);
!!42;
__END__
=pod
=encoding utf-8
=for :stopwords Chris Weyl
=head1 NAME
MooseX::AbstractMethod - Declare methods requirements that must be satisfied
=head1 VERSION
This document describes version 0.004 of MooseX::AbstractMethod - released August 31, 2012 as part of MooseX-AbstractMethod.
=head1 SYNOPSIS
use Moose;
use MooseX::Abstract;
requires 'bar';
# synonm to 'requires'
abstract 'foo';
=head1 DESCRIPTION
This extensions allows classes to flag certain methods as being required to be
implemented by a subclass, much as a L<Moose::Role> does with 'requires'.
=head1 USAGE
As in the synopsis, simply mark certain methods as being required by
subclasses by passing their names to "abstract" or "requires". This will
cause a method of the same name to be installed in the class that will die
horribly if it's ever called. Additionally, when a class is made immutable,
all of its methods are checked to see if they're marked as abstract; if any
abstract methods exists that were not created in the current class, we die
horribly.
Checking for method satisfaction on make_immutable isn't perfect, but AFAICT
it's the most reasonable approach possible at the moment. (Corrections
welcome.)
=head1 NEW SUGAR
=head2 abstract
abstract() allows one to declare a method dependency that must be satisfied by a
subclass before it is invoked, and before the subclass is made immutable.
abstract 'method_name_that_must_be_satisfied';
=head2 requires
requires() is a synonym for abstract() and works in the way you'd expect.
=head1 SOURCE
The development version is on github at L<http://github.com/RsrchBoy/moosex-abstractmethod>
and may be cloned from L<git://github.com/RsrchBoy/moosex-abstractmethod.git>
=head1 BUGS
Please report any bugs or feature requests on the bugtracker website
https://github.com/RsrchBoy/moosex-abstractmethod/issues
When submitting a bug or request, please include a test-file or a
patch to an existing test-file that illustrates the bug or desired
feature.
=head1 AUTHOR
Chris Weyl <cweyl@alumni.drew.edu>
=head1 COPYRIGHT AND LICENSE
This software is Copyright (c) 2011 by Chris Weyl.
This is free software, licensed under:
The GNU Lesser General Public License, Version 2.1, February 1999
=cut
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