/usr/lib/perl5/Moose/Cookbook/Extending/Recipe3.pod is in libmoose-perl 2.0401-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 | package Moose::Cookbook::Extending::Recipe3;
# ABSTRACT: Providing an alternate base object class
=pod
=head1 NAME
Moose::Cookbook::Extending::Recipe3 - Providing an alternate base object class
=head1 VERSION
version 2.0401
=head1 SYNOPSIS
package MyApp::Base;
use Moose;
extends 'Moose::Object';
before 'new' => sub { warn "Making a new " . $_[0] };
no Moose;
package MyApp::UseMyBase;
use Moose ();
use Moose::Exporter;
Moose::Exporter->setup_import_methods( also => 'Moose' );
sub init_meta {
shift;
return Moose->init_meta( @_, base_class => 'MyApp::Base' );
}
=head1 DESCRIPTION
A common extension is to provide an alternate base class. One way to
do that is to make a C<MyApp::Base> and add C<S<extends
'MyApp::Base'>> to every class in your application. That's pretty
tedious. Instead, you can create a Moose-alike module that sets the
base object class to C<MyApp::Base> for you.
Then, instead of writing C<S<use Moose>> you can write C<S<use
MyApp::UseMyBase>>.
In this particular example, our base class issues some debugging
output every time a new object is created, but you can think of some
more interesting things to do with your own base class.
This uses the magic of L<Moose::Exporter>. When we call C<<
Moose::Exporter->setup_import_methods( also => 'Moose' ) >> it builds
C<import> and C<unimport> methods for you. The C<< also => 'Moose' >>
bit says that we want to export everything that Moose does.
The C<import> method that gets created will call our C<init_meta>
method, passing it C<< for_caller => $caller >> as its
arguments. The C<$caller> is set to the class that actually imported
us in the first place.
See the L<Moose::Exporter> docs for more details on its API.
=for testing-SETUP use Test::Requires {
'Test::Output' => '0',
};
=head1 USING MyApp::UseMyBase
To actually use our new base class, we simply use C<MyApp::UseMyBase>
I<instead> of C<Moose>. We get all the Moose sugar plus our new base
class.
package Foo;
use MyApp::UseMyBase;
has 'size' => ( is => 'rw' );
no MyApp::UseMyBase;
=head1 CONCLUSION
This is an awful lot of magic for a simple base class. You will often
want to combine a metaclass trait with a base class extension, and
that's when this technique is useful.
=begin testing
{
package Foo;
MyApp::UseMyBase->import;
has( 'size' => ( is => 'rw' ) );
}
ok( Foo->isa('MyApp::Base'), 'Foo isa MyApp::Base' );
ok( Foo->can('size'), 'Foo has a size method' );
my $foo;
stderr_like(
sub { $foo = Foo->new( size => 2 ) },
qr/^Making a new Foo/,
'got expected warning when calling Foo->new'
);
is( $foo->size(), 2, '$foo->size is 2' );
=end testing
=head1 AUTHOR
Moose is maintained by the Moose Cabal, along with the help of many contributors. See L<Moose/CABAL> and L<Moose/CONTRIBUTORS> for details.
=head1 COPYRIGHT AND LICENSE
This software is copyright (c) 2011 by Infinity Interactive, Inc..
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
=cut
__END__
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