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1 | |
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2 | package # hide the package from PAUSE |
3 | Perl6Attribute; |
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4 | |
5 | use strict; |
6 | use warnings; |
7 | |
8 | our $VERSION = '0.01'; |
9 | |
10 | use base 'Class::MOP::Attribute'; |
11 | |
12 | sub new { |
13 | my ($class, $attribute_name, %options) = @_; |
14 | |
15 | # extract the sigil and accessor name |
16 | my ($sigil, $accessor_name) = ($attribute_name =~ /^([\$\@\%])\.(.*)$/); |
17 | |
18 | # pass the accessor name |
19 | $options{accessor} = $accessor_name; |
20 | |
21 | # create a default value based on the sigil |
22 | $options{default} = sub { [] } if ($sigil eq '@'); |
23 | $options{default} = sub { {} } if ($sigil eq '%'); |
24 | |
25 | $class->SUPER::new($attribute_name, %options); |
26 | } |
27 | |
28 | 1; |
29 | |
30 | __END__ |
31 | |
32 | =pod |
33 | |
34 | =head1 NAME |
35 | |
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36 | Perl6Attribute - An example attribute metaclass for Perl 6 style attributes |
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37 | |
38 | =head1 SYNOPSIS |
39 | |
40 | package Foo; |
41 | |
42 | use Class::MOP 'meta'; |
43 | |
44 | Foo->meta->add_attribute(Perl6Attribute->new('$.foo')); |
45 | Foo->meta->add_attribute(Perl6Attribute->new('@.bar')); |
46 | Foo->meta->add_attribute(Perl6Attribute->new('%.baz')); |
47 | |
48 | sub new { |
49 | my $class = shift; |
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50 | bless $class->meta->construct_instance(@_) => $class; |
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51 | } |
52 | |
53 | =head1 DESCRIPTION |
54 | |
55 | This is an attribute metaclass which implements Perl 6 style |
56 | attributes, including the auto-generating accessors. |
57 | |
58 | This code is very simple, we only need to subclass |
59 | C<Class::MOP::Attribute> and override C<&new>. Then we just |
60 | pre-process the attribute name, and create the accessor name |
61 | and default value based on it. |
62 | |
63 | More advanced features like the C<handles> trait (see |
64 | L<Perl6::Bible/A12>) can be accomplished as well doing the |
65 | same pre-processing approach. This is left as an exercise to |
66 | the reader though (if you do it, please send me a patch |
67 | though, and will update this). |
68 | |
69 | =head1 AUTHOR |
70 | |
71 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
72 | |
73 | =head1 COPYRIGHT AND LICENSE |
74 | |
75 | Copyright 2006 by Infinity Interactive, Inc. |
76 | |
77 | L<http://www.iinteractive.com> |
78 | |
79 | This library is free software; you can redistribute it and/or modify |
80 | it under the same terms as Perl itself. |
81 | |
82 | =cut |