6 Moose::Cookbook::Extending::Recipe2 - Acting like Moose.pm and providing sugar Moose-style
10 package MyApp::Mooseish;
15 our @EXPORT = qw( has_table );
22 my $caller = caller();
24 return if $caller eq 'main';
26 Moose::init_meta( $caller,
27 undef, # object base class
31 Moose->import( { into => $caller }, @_ );
33 __PACKAGE__->export_to_level( 1, @_ );
37 my $caller = caller();
40 foreach my $name (@EXPORT) {
41 if ( defined &{ $caller . '::' . $name } ) {
42 my $keyword = \&{ $caller . '::' . $name };
44 my ($pkg_name) = Class::MOP::get_code_info($keyword);
46 next if $pkg_name ne __PACKAGE__;
48 delete ${ $caller . '::' }{$name};
52 Moose::unimport( { into_level => 1 } );
56 my $caller = caller();
58 $caller->meta()->table(shift);
63 The code above shows what it takes to provide an import-based
64 interface just like C<Moose.pm>.
66 Given the above code, you can now replace all instances of C<use
67 Moose> with C<use MyApp::Mooseish>. Similarly, C<no Moose> is now
68 replaced with C<no MyApp::Mooseish>.
72 This recipe covers a fairly undocumented and ugly part of Moose, and
73 the techniques described here may be deprecated in a future
74 release. If this happens, there will be plenty of warning, as a number
75 of C<MooseX> modules on CPAN already use these techniques.
79 The purpose of all this code is to provide a Moose-like
80 interface. Here's what it would look like in actual use:
95 All of the normal Moose sugar (C<has()>, C<with()>, etc) is available
96 when you C<use MyApp::Mooseish>.
100 The first bit of magic is the call to C<Moose::init_meta()>. What this
101 does is create a metaclass for the specified class. Normally, this is
102 called by C<Moose.pm> in its own C<import()> method. However, we can
103 call it first in order to provide an alternate metaclass class. We
104 could also provide an alternate base object class to replace
105 C<Moose::Object> (see L<Moose::Cookbook::Extending::Recipe1> for an
108 The C<Moose::init_meta()> call takes three parameters. The first is
109 the class for which we are initializing a metaclass object. The second
110 is the base object, which is L<Moose::Object> by default. The third
111 argument is the metaclass class, which is C<Moose::Meta::Class> by
114 The next bit of magic is this:
116 Moose->import( { into => $caller } );
118 This use of "into" is actually part of the C<Sub::Exporter> API, which
119 C<Moose.pm> uses internally to export things like C<has()> and
122 Finally, we call C<< __PACKAGE__->export_to_level() >>. This method
123 actually comes from C<Exporter>.
125 This is all a bit fragile since it doesn't stack terribly well. You
126 can basically only have one Moose-alike module. This may be fixed in
127 the still-notional C<MooseX::Exporter> module someday.
129 The C<unimport()> subroutine is basically a copy of the C<unimport()>
130 from C<Moose.pm>. You can copy this verbatim into your code. Again,
131 this doesn't stack well.
133 Finally, we have our C<has_table()> subroutine. This provides a bit of
134 sugar that looks a lot like C<has()>.
138 Dave Rolsky E<lt>autarch@urth.orgE<gt>
140 =head1 COPYRIGHT AND LICENSE
142 Copyright 2006-2008 by Infinity Interactive, Inc.
144 L<http://www.iinteractive.com>
146 This library is free software; you can redistribute it and/or modify
147 it under the same terms as Perl itself.