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1 | package MooseX::UndefTolerant; |
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2 | |
3 | use Moose qw(); |
4 | use Moose::Exporter; |
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5 | |
6 | use MooseX::UndefTolerant::Attribute; |
7 | |
8 | our $VERSION = '0.01'; |
9 | |
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10 | Moose::Exporter->setup_import_methods( |
11 | attribute_metaclass_roles => [ 'MooseX::UndefTolerant::Attribute' ] |
12 | ); |
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13 | |
14 | 1; |
15 | |
16 | __END__ |
17 | |
18 | =head1 NAME |
19 | |
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20 | MooseX::UndefTolerant - Make your attribute(s) tolerant to undef intitialization |
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21 | |
22 | =head1 SYNOPSIS |
23 | |
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24 | package My::Class; |
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25 | |
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26 | use Moose; |
27 | use MooseX::UndefTolerant; |
28 | |
29 | has 'name' => ( |
30 | is => 'ro', |
31 | isa => 'Str', |
32 | predicate => 'has_name' |
33 | ); |
34 | |
35 | # Meanwhile, under the city... |
36 | |
37 | # Doesn't explode |
38 | my $class = My::Class->new(name => undef); |
39 | $class->has_name # False! |
40 | |
41 | Or, if you only want one attribute to have this behaviour: |
42 | |
43 | package My:Class; |
44 | use Moose; |
45 | |
46 | use MooseX::UndefTolerant::Attribute; |
47 | |
48 | has 'bar' => ( |
49 | traits => [ qw(MooseX::UndefTolerant::Attribute)], |
50 | is => 'ro', |
51 | isa => 'Num', |
52 | predicate => 'has_bar' |
53 | ); |
54 | |
55 | =head1 DESCRIPTION |
56 | |
57 | Loading this module in your L<Moose> class makes initialization of your |
58 | attributes tolerant of undef. If you specify the value of undef to any of |
59 | the attributes they will not be initialized. Effectively behaving as if you |
60 | had not provided a value at all. |
61 | |
62 | =head1 MOTIVATION |
63 | |
64 | I often found myself in this quandry: |
65 | |
66 | package My:Class; |
67 | use Moose; |
68 | |
69 | has 'foo' => ( |
70 | is => 'ro', |
71 | isa => 'Str', |
72 | ); |
73 | |
74 | # ... then |
75 | |
76 | my $foo = ... # get the param from something |
77 | |
78 | my $class = My:Class->new(foo => $foo, bar => 123); |
79 | |
80 | What if foo is undefined? I didn't want to change my attribute to be |
81 | Maybe[Str] and I still want my predicate (C<has_foo>) to work. The only |
82 | real solution was: |
83 | |
84 | if(defined($foo)) { |
85 | $class = My:CLass->new(foo => $foo, bar => 123); |
86 | } else { |
87 | $class = My:CLass->new(bar => 123); |
88 | } |
89 | |
90 | Or some type of codemulch using ternarys. This module allows you to make |
91 | your attributes more tolerant of undef so that you can keep the first |
92 | example: have your cake and eat it too! |
93 | |
94 | =head1 PER ATTRIBUTE |
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95 | |
96 | =head1 AUTHOR |
97 | |
98 | Cory G Watson, C<< <gphat at cpan.org> >> |
99 | |
100 | =head1 ACKNOWLEDGEMENTS |
101 | |
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102 | Many thanks to the crew in #moose who talked me through this module: |
103 | |
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104 | Hans Dieter Pearcey (confound) |
105 | |
106 | Jesse Luehrs (doy) |
107 | |
108 | Tomas Doran (t0m) |
109 | |
110 | Dylan Hardison (dylan) |
111 | |
112 | Jay Shirley (jshirley) |
113 | |
114 | Mike Eldridge (diz) |
115 | |
116 | =head1 COPYRIGHT & LICENSE |
117 | |
118 | Copyright 2009 Cory G Watson. |
119 | |
120 | This program is free software; you can redistribute it and/or modify it |
121 | under the terms of either: the GNU General Public License as published |
122 | by the Free Software Foundation; or the Artistic License. |
123 | |
124 | See http://dev.perl.org/licenses/ for more information. |
125 | |
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126 | =cut |