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1 | |
2 | package # hide the package from PAUSE |
3 | Perl6Attribute; |
4 | |
5 | use strict; |
6 | use warnings; |
7 | |
8 | our $VERSION = '0.02'; |
9 | |
10 | use base 'Class::MOP::Attribute'; |
11 | |
12 | Perl6Attribute->meta->add_around_method_modifier('new' => sub { |
13 | my $cont = shift; |
14 | my ($class, $attribute_name, %options) = @_; |
15 | |
16 | # extract the sigil and accessor name |
17 | my ($sigil, $accessor_name) = ($attribute_name =~ /^([\$\@\%])\.(.*)$/); |
18 | |
19 | # pass the accessor name |
20 | $options{accessor} = $accessor_name; |
21 | |
22 | # create a default value based on the sigil |
23 | $options{default} = sub { [] } if ($sigil eq '@'); |
24 | $options{default} = sub { {} } if ($sigil eq '%'); |
25 | |
26 | $cont->($class, $attribute_name, %options); |
27 | }); |
28 | |
29 | 1; |
30 | |
31 | __END__ |
32 | |
33 | =pod |
34 | |
35 | =head1 NAME |
36 | |
37 | Perl6Attribute - An example attribute metaclass for Perl 6 style attributes |
38 | |
39 | =head1 SYNOPSIS |
40 | |
41 | package Foo; |
42 | |
43 | Foo->meta->add_attribute(Perl6Attribute->new('$.foo')); |
44 | Foo->meta->add_attribute(Perl6Attribute->new('@.bar')); |
45 | Foo->meta->add_attribute(Perl6Attribute->new('%.baz')); |
46 | |
47 | sub new { |
48 | my $class = shift; |
49 | $class->meta->new_object(@_); |
50 | } |
51 | |
52 | =head1 DESCRIPTION |
53 | |
54 | This is an attribute metaclass which implements Perl 6 style |
55 | attributes, including the auto-generating accessors. |
56 | |
57 | This code is very simple, we only need to subclass |
58 | C<Class::MOP::Attribute> and override C<&new>. Then we just |
59 | pre-process the attribute name, and create the accessor name |
60 | and default value based on it. |
61 | |
62 | More advanced features like the C<handles> trait (see |
63 | L<Perl6::Bible/A12>) can be accomplished as well doing the |
64 | same pre-processing approach. This is left as an exercise to |
65 | the reader though (if you do it, please send me a patch |
66 | though, and will update this). |
67 | |
68 | =head1 AUTHORS |
69 | |
70 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
71 | |
72 | Yuval Kogman E<lt>nothingmuch@woobling.comE<gt> |
73 | |
74 | =head1 COPYRIGHT AND LICENSE |
75 | |
76 | Copyright 2006-2008 by Infinity Interactive, Inc. |
77 | |
78 | L<http://www.iinteractive.com> |
79 | |
80 | This library is free software; you can redistribute it and/or modify |
81 | it under the same terms as Perl itself. |
82 | |
83 | =cut |