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1 | package Moose::Meta::TypeConstraint::DuckType; |
2 | |
3 | use strict; |
4 | use warnings; |
5 | use metaclass; |
6 | |
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7 | use B; |
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8 | use Scalar::Util 'blessed'; |
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9 | use List::MoreUtils qw(all); |
10 | use Moose::Util 'english_list'; |
11 | |
12 | use Moose::Util::TypeConstraints (); |
13 | |
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14 | use base 'Moose::Meta::TypeConstraint'; |
15 | |
16 | __PACKAGE__->meta->add_attribute('methods' => ( |
17 | accessor => 'methods', |
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18 | Class::MOP::_definition_context(), |
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19 | )); |
20 | |
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21 | my $inliner = sub { |
22 | my $self = shift; |
23 | my $val = shift; |
24 | |
21ddc881 |
25 | return 'my $val = ' . $val . '; Scalar::Util::blessed($val) ' |
26 | . '&& Scalar::Util::blessed($val) ne "Regexp" ' |
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27 | . '&& &List::MoreUtils::all(' |
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28 | . 'sub { $val->can($_) }, ' |
3975b592 |
29 | . join(', ', map { B::perlstring($_) } @{ $self->methods }) |
30 | . ')'; |
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31 | }; |
32 | |
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33 | sub new { |
34 | my ( $class, %args ) = @_; |
35 | |
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36 | $args{parent} |
37 | = Moose::Util::TypeConstraints::find_type_constraint('Object'); |
38 | |
39 | my @methods = @{ $args{methods} }; |
40 | $args{constraint} = sub { |
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41 | my $val = $_[0]; |
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42 | blessed($val) && blessed($val) ne 'Regexp' |
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43 | && all { $val->can($_) } @methods; |
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44 | }; |
45 | |
46 | $args{inlined} = $inliner; |
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47 | |
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48 | my $self = $class->SUPER::new(\%args); |
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49 | |
50 | $self->compile_type_constraint() |
51 | unless $self->_has_compiled_type_constraint; |
52 | |
53 | return $self; |
54 | } |
55 | |
56 | sub equals { |
57 | my ( $self, $type_or_name ) = @_; |
58 | |
59 | my $other = Moose::Util::TypeConstraints::find_type_constraint($type_or_name); |
60 | |
61 | return unless $other->isa(__PACKAGE__); |
62 | |
63 | my @self_methods = sort @{ $self->methods }; |
64 | my @other_methods = sort @{ $other->methods }; |
65 | |
66 | return unless @self_methods == @other_methods; |
67 | |
68 | while ( @self_methods ) { |
69 | my $method = shift @self_methods; |
70 | my $other_method = shift @other_methods; |
71 | |
72 | return unless $method eq $other_method; |
73 | } |
74 | |
75 | return 1; |
76 | } |
77 | |
78 | sub constraint { |
79 | my $self = shift; |
80 | |
81 | my @methods = @{ $self->methods }; |
82 | |
83 | return sub { |
84 | my $obj = shift; |
85 | return all { $obj->can($_) } @methods |
86 | }; |
87 | } |
88 | |
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89 | sub create_child_type { |
90 | my ($self, @args) = @_; |
91 | return Moose::Meta::TypeConstraint->new(@args, parent => $self); |
92 | } |
93 | |
94 | sub get_message { |
95 | my $self = shift; |
96 | my ($value) = @_; |
97 | |
98 | if ($self->has_message) { |
99 | return $self->SUPER::get_message(@_); |
100 | } |
101 | |
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102 | return $self->SUPER::get_message($value) unless blessed($value); |
103 | |
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104 | my @methods = grep { !$value->can($_) } @{ $self->methods }; |
105 | my $class = blessed $value; |
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106 | $class ||= $value; |
107 | |
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108 | return $class |
109 | . " is missing methods " |
110 | . english_list(map { "'$_'" } @methods); |
111 | } |
112 | |
113 | 1; |
114 | |
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115 | # ABSTRACT: Type constraint for duck typing |
116 | |
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117 | __END__ |
118 | |
119 | =pod |
120 | |
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121 | =head1 DESCRIPTION |
122 | |
123 | This class represents type constraints based on an enumerated list of |
124 | required methods. |
125 | |
126 | =head1 INHERITANCE |
127 | |
128 | C<Moose::Meta::TypeConstraint::DuckType> is a subclass of |
129 | L<Moose::Meta::TypeConstraint>. |
130 | |
131 | =head1 METHODS |
132 | |
133 | =over 4 |
134 | |
135 | =item B<< Moose::Meta::TypeConstraint::DuckType->new(%options) >> |
136 | |
137 | This creates a new duck type constraint based on the given |
138 | C<%options>. |
139 | |
140 | It takes the same options as its parent, with several |
141 | exceptions. First, it requires an additional option, C<methods>. This |
142 | should be an array reference containing a list of required method |
143 | names. Second, it automatically sets the parent to the C<Object> type. |
144 | |
145 | Finally, it ignores any provided C<constraint> option. The constraint |
146 | is generated automatically based on the provided C<methods>. |
147 | |
148 | =item B<< $constraint->methods >> |
149 | |
150 | Returns the array reference of required methods provided to the |
151 | constructor. |
152 | |
153 | =item B<< $constraint->create_child_type >> |
154 | |
155 | This returns a new L<Moose::Meta::TypeConstraint> object with the type |
156 | as its parent. |
157 | |
158 | Note that it does I<not> return a C<Moose::Meta::TypeConstraint::DuckType> |
159 | object! |
160 | |
161 | =back |
162 | |
163 | =head1 BUGS |
164 | |
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165 | See L<Moose/BUGS> for details on reporting bugs. |
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166 | |
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167 | =cut |
168 | |