Revision history for Perl extension Class-MOP.
+0.04
+ - some documentation suggestions from #perl6
+
0.03 Fri Feb. 3, 2006
- converted to Module::Build instead of EU::MM
--- /dev/null
+
+package # hide the package from PAUSE
+ AttributesWithHistory;
+
+use strict;
+use warnings;
+
+use Class::MOP 'meta';
+
+our $VERSION = '0.01';
+
+use base 'Class::MOP::Attribute';
+
+# this is for an extra attribute constructor
+# option, which is to be able to create a
+# way for the class to access the history
+__PACKAGE__->meta->add_attribute(
+ Class::MOP::Attribute->new('history_accessor' => (
+ reader => 'history_accessor',
+ init_arg => 'history_accessor',
+ predicate => 'has_history_accessor',
+ ))
+);
+
+# this is a place to store the actual
+# history of the attribute
+__PACKAGE__->meta->add_attribute(
+ Class::MOP::Attribute->new('_history' => (
+ accessor => '_history',
+ default => sub { [] },
+ ))
+);
+
+# generate the methods
+
+sub generate_history_accessor_method {
+ my ($self, $attr_name) = @_;
+ eval qq{sub {
+ \@\{\$_[0]->meta->get_attribute('$attr_name')->_history()\};
+ }};
+}
+
+sub generate_accessor_method {
+ my ($self, $attr_name) = @_;
+ eval qq{sub {
+ if (scalar(\@_) == 2) {
+ push \@\{\$_[0]->meta->get_attribute('$attr_name')->_history()\} => \$_[1];
+ \$_[0]->{'$attr_name'} = \$_[1];
+ }
+ \$_[0]->{'$attr_name'};
+ }};
+}
+
+sub generate_writer_method {
+ my ($self, $attr_name) = @_;
+ eval qq{sub {
+ push \@\{\$_[0]->meta->get_attribute('$attr_name')->_history()\} => \$_[1];
+ \$_[0]->{'$attr_name'} = \$_[1];
+ }};
+}
+
+sub install_accessors {
+ my $self = shift;
+ # do as we normall do ...
+ $self->SUPER::install_accessors();
+ # and now add the history accessor
+ $self->associated_class->add_method(
+ $self->process_accessors('history_accessor' => $self->history_accessor())
+ ) if $self->has_history_accessor();
+ return;
+}
+
+1;
+
+=pod
+
+=head1 NAME
+
+AttributesWithHistory - An example attribute metaclass which keeps a history of changes
+
+=head1 SYSNOPSIS
+
+ package Foo;
+
+ use Class::MOP 'meta';
+
+ Foo->meta->add_attribute(AttributesWithHistory->new('foo' => (
+ accessor => 'foo',
+ history_accessor => 'get_foo_history',
+ )));
+
+ Foo->meta->add_attribute(AttributesWithHistory->new('bar' => (
+ reader => 'get_bar',
+ writer => 'set_bar',
+ history_accessor => 'get_bar_history',
+ )));
+
+ sub new {
+ my $class = shift;
+ bless $class->meta->construct_instance() => $class;
+ }
+
+=head1 DESCRIPTION
+
+This is an example of an attribute metaclass which keeps a
+record of all the values it has been assigned. It stores the
+history as a field in the attribute meta-object, and will
+autogenerate a means of accessing that history for the class
+which these attributes are added too.
+
+=head1 AUTHOR
+
+Stevan Little E<lt>stevan@iinteractive.comE<gt>
+
+=head1 COPYRIGHT AND LICENSE
+
+Copyright 2006 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.
+
+=cut
+
=head2 What changes do I have to make to use this module?
This module was designed to be as unintrusive as possible. Many of
-it's features are accessible without B<any> change to your existsing
+its features are accessible without B<any> change to your existsing
code at all. It is meant to be a compliment to your existing code and
not an intrusion on your code base. Unlike many other B<Class::>
modules, this module B<does not> require you subclass it, or even that
if (my $method = $self->$generator($self->name)) {
return ($accessor => Class::MOP::Attribute::Accessor->wrap($method));
}
- confess "Could not create the methods for " . $self->name . " because : $@";
+ confess "Could not create the '$type' method for " . $self->name . " because : $@";
}
}
relationships of the class the B<Class::MOP::Class> instance is
associated with. Basically, it can get and set the C<@ISA> for you.
+B<NOTE:>
+Perl will occasionally perform some C<@ISA> and method caching, if
+you decide to change your superclass relationship at runtime (which
+is quite insane and very much not recommened), then you should be
+aware of this and the fact that this module does not make any
+attempt to address this issue.
+
=item B<class_precedence_list>
This computes the a list of all the class's ancestors in the same order
--- /dev/null
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+
+use Test::More tests => 19;
+use File::Spec;
+
+BEGIN {
+ use_ok('Class::MOP');
+ require_ok(File::Spec->catdir('examples', 'AttributesWithHistory.pod'));
+}
+
+{
+ package Foo;
+
+ use Class::MOP 'meta';
+
+ Foo->meta->add_attribute(AttributesWithHistory->new('foo' => (
+ accessor => 'foo',
+ history_accessor => 'get_foo_history',
+ )));
+
+ Foo->meta->add_attribute(AttributesWithHistory->new('bar' => (
+ reader => 'get_bar',
+ writer => 'set_bar',
+ history_accessor => 'get_bar_history',
+ )));
+
+ sub new {
+ my $class = shift;
+ bless $class->meta->construct_instance() => $class;
+ }
+}
+
+my $foo = Foo->new();
+isa_ok($foo, 'Foo');
+
+can_ok($foo, 'foo');
+can_ok($foo, 'get_foo_history');
+can_ok($foo, 'set_bar');
+can_ok($foo, 'get_bar');
+can_ok($foo, 'get_bar_history');
+
+is($foo->foo, undef, '... foo is not yet defined');
+is_deeply(
+ [ $foo->get_foo_history() ],
+ [ ],
+ '... got correct empty history for foo');
+
+$foo->foo(42);
+is($foo->foo, 42, '... foo == 42');
+is_deeply(
+ [ $foo->get_foo_history() ],
+ [ 42 ],
+ '... got correct history for foo');
+
+$foo->foo(43);
+$foo->foo(44);
+$foo->foo(45);
+$foo->foo(46);
+
+is_deeply(
+ [ $foo->get_foo_history() ],
+ [ 42, 43, 44, 45, 46 ],
+ '... got correct history for foo');
+
+is($foo->get_bar, undef, '... bar is not yet defined');
+is_deeply(
+ [ $foo->get_bar_history() ],
+ [ ],
+ '... got correct empty history for foo');
+
+
+$foo->set_bar("FOO");
+is($foo->get_bar, "FOO", '... bar == "FOO"');
+is_deeply(
+ [ $foo->get_bar_history() ],
+ [ "FOO" ],
+ '... got correct history for foo');
+
+$foo->set_bar("BAR");
+$foo->set_bar("BAZ");
+
+is_deeply(
+ [ $foo->get_bar_history() ],
+ [ qw/FOO BAR BAZ/ ],
+ '... got correct history for bar');
+
+is_deeply(
+ [ $foo->get_foo_history() ],
+ [ 42, 43, 44, 45, 46 ],
+ '... still have the correct history for foo');
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