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1 | package Moose::Meta::TypeConstraint::Parameterizable; |
2 | |
3 | use strict; |
4 | use warnings; |
5 | use metaclass; |
6 | |
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7 | our $VERSION = '0.71_01'; |
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8 | $VERSION = eval $VERSION; |
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9 | our $AUTHORITY = 'cpan:STEVAN'; |
10 | |
11 | use base 'Moose::Meta::TypeConstraint'; |
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12 | use Moose::Meta::TypeConstraint::Parameterized; |
13 | use Moose::Util::TypeConstraints (); |
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14 | |
15 | __PACKAGE__->meta->add_attribute('constraint_generator' => ( |
16 | accessor => 'constraint_generator', |
17 | predicate => 'has_constraint_generator', |
18 | )); |
19 | |
20 | sub generate_constraint_for { |
21 | my ($self, $type) = @_; |
22 | |
23 | return unless $self->has_constraint_generator; |
24 | |
25 | return $self->constraint_generator->($type->type_parameter) |
26 | if $type->is_subtype_of($self->name); |
27 | |
28 | return $self->_can_coerce_constraint_from($type) |
29 | if $self->has_coercion |
30 | && $self->coercion->has_coercion_for_type($type->parent->name); |
31 | |
32 | return; |
33 | } |
34 | |
35 | sub _can_coerce_constraint_from { |
36 | my ($self, $type) = @_; |
37 | my $coercion = $self->coercion; |
38 | my $constraint = $self->constraint_generator->($type->type_parameter); |
39 | return sub { |
40 | local $_ = $coercion->coerce($_); |
41 | $constraint->(@_); |
42 | }; |
43 | } |
44 | |
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45 | sub _parse_type_parameter { |
46 | my ($self, $type_parameter) = @_; |
47 | return Moose::Util::TypeConstraints::find_or_create_isa_type_constraint($type_parameter); |
48 | } |
49 | |
50 | sub parameterize { |
51 | my ($self, $type_parameter) = @_; |
52 | |
53 | my $contained_tc = $self->_parse_type_parameter($type_parameter); |
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54 | |
55 | ## The type parameter should be a subtype of the parent's type parameter |
56 | ## if there is one. |
57 | |
58 | if(my $parent = $self->parent) { |
59 | if($parent->can('type_parameter')) { |
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60 | unless ( $contained_tc->is_a_type_of($parent->type_parameter) ) { |
61 | require Moose; |
62 | Moose->throw_error("$type_parameter is not a subtype of ".$parent->type_parameter); |
63 | } |
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64 | } |
65 | } |
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66 | |
67 | if ( $contained_tc->isa('Moose::Meta::TypeConstraint') ) { |
68 | my $tc_name = $self->name . '[' . $contained_tc->name . ']'; |
69 | return Moose::Meta::TypeConstraint::Parameterized->new( |
70 | name => $tc_name, |
71 | parent => $self, |
72 | type_parameter => $contained_tc, |
73 | ); |
74 | } |
75 | else { |
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76 | require Moose; |
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77 | Moose->throw_error("The type parameter must be a Moose meta type"); |
78 | } |
79 | } |
80 | |
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81 | |
82 | 1; |
83 | |
84 | __END__ |
85 | |
86 | |
87 | =pod |
88 | |
89 | =head1 NAME |
90 | |
91 | Moose::Meta::TypeConstraint::Parameterizable - Higher Order type constraints for Moose |
92 | |
93 | =head1 METHODS |
94 | |
95 | =over 4 |
96 | |
97 | =item B<constraint_generator> |
98 | |
99 | =item B<has_constraint_generator> |
100 | |
101 | =item B<generate_constraint_for> |
102 | |
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103 | =item B<parameterize> |
104 | |
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105 | Given a single type constraint or type constraint string, this method |
106 | parameterizes the type based on the given argument. |
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107 | |
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108 | =item B<meta> |
109 | |
110 | =back |
111 | |
112 | =head1 BUGS |
113 | |
114 | All complex software has bugs lurking in it, and this module is no |
115 | exception. If you find a bug please either email me, or add the bug |
116 | to cpan-RT. |
117 | |
118 | =head1 AUTHOR |
119 | |
120 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
121 | |
122 | =head1 COPYRIGHT AND LICENSE |
123 | |
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124 | Copyright 2006-2009 by Infinity Interactive, Inc. |
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125 | |
126 | L<http://www.iinteractive.com> |
127 | |
128 | This library is free software; you can redistribute it and/or modify |
129 | it under the same terms as Perl itself. |
130 | |
131 | =cut |