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1 | package MooseX::Meta::TypeConstraint::Structured; |
2 | |
3 | use 5.8.8; ## Minimum tested Perl Version |
4 | use Moose; |
5 | use Moose::Util::TypeConstraints; |
6 | |
7 | extends 'Moose::Meta::TypeConstraint'; |
8 | |
9 | our $AUTHORITY = 'cpan:JJNAPIORK'; |
10 | |
11 | =head1 NAME |
12 | |
13 | MooseX::Meta::TypeConstraint::Structured - Structured Type Constraints |
14 | |
15 | =head1 VERSION |
16 | |
17 | 0.01 |
18 | |
19 | =cut |
20 | |
21 | our $VERSION = '0.01'; |
22 | |
23 | =head1 DESCRIPTION |
24 | |
25 | Structured type constraints let you assign an internal pattern of type |
26 | constraints to a 'container' constraint. The goal is to make it easier to |
27 | declare constraints like "ArrayRef[Int, Int, Str]" where the constraint is an |
28 | ArrayRef of three elements and the internal constraint on the three is Int, Int |
29 | and Str. |
30 | |
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31 | To accomplish this, we add an attribute to the base L<Moose::Meta::TypeConstraint> |
32 | to hold a L</signature>, which is a reference to a pattern of type constraints. |
33 | We then override L</constraint> to check our incoming value to the attribute |
34 | against this signature pattern. |
35 | |
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36 | =head1 SUBTYPES |
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37 | |
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38 | The following subtypes and coercions are defined in this class. |
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39 | |
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40 | =head2 MooseX::Meta::TypeConstraint::Structured::Signature |
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41 | |
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42 | This is a type constraint to normalize the incoming L</signature>. We want |
43 | everything as a HashRef in the end. |
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44 | |
45 | =cut |
46 | |
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47 | subtype 'MooseX::Meta::TypeConstraint::Structured::Signature', |
48 | as 'HashRef[Object]', |
49 | where { |
50 | my %signature = %$_; |
51 | foreach my $key (keys %signature) { |
52 | $signature{$key}->isa('Moose::Meta::TypeConstraint'); |
53 | } 1; |
54 | }; |
55 | |
56 | coerce 'MooseX::Meta::TypeConstraint::Structured::Signature', |
57 | from 'ArrayRef[Object]', |
58 | via { |
59 | my @signature = @$_; |
60 | my %hashed_signature = map { $_ => $signature[$_] } 0..$#signature; |
61 | \%hashed_signature; |
62 | }; |
63 | |
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64 | =head1 ATTRIBUTES |
65 | |
66 | This class defines the following attributes. |
67 | |
68 | =head2 signature |
69 | |
70 | This is a signature of internal contraints for the contents of the outer |
71 | contraint container. |
72 | |
73 | =cut |
74 | |
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75 | has 'signature' => ( |
76 | is=>'ro', |
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77 | isa=>'MooseX::Meta::TypeConstraint::Structured::Signature', |
78 | coerce=>1, |
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79 | required=>1, |
80 | ); |
81 | |
82 | =head1 METHODS |
83 | |
84 | This class defines the following methods. |
85 | |
86 | =head2 _normalize_args |
87 | |
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88 | Get arguments into a known state or die trying. Ideally we try to make this |
89 | into a HashRef so we can match it up with the L</signature> HashRef. |
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90 | |
91 | =cut |
92 | |
93 | sub _normalize_args { |
94 | my ($self, $args) = @_; |
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95 | if(defined $args) { |
96 | if(ref $args eq 'ARRAY') { |
97 | return map { $_ => $args->[$_] } (0..$#$args); |
98 | } elsif (ref $args eq 'HASH') { |
99 | return %$args; |
100 | } else { |
101 | confess 'Signature must be a reference'; |
102 | } |
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103 | } else { |
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104 | confess 'Signature cannot be empty'; |
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105 | } |
106 | } |
107 | |
108 | =head2 constraint |
109 | |
110 | The constraint is basically validating the L</signature> against the incoming |
111 | |
112 | =cut |
113 | |
114 | sub constraint { |
115 | my $self = shift; |
116 | return sub { |
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117 | my %args = $self->_normalize_args(shift); |
118 | foreach my $idx (keys %{$self->signature}) { |
119 | my $type_constraint = $self->signature->{$idx}; |
120 | if(my $error = $type_constraint->validate($args{$idx})) { |
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121 | confess $error; |
122 | } |
123 | } 1; |
124 | }; |
125 | } |
126 | |
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127 | =head2 equals |
128 | |
129 | modifier to make sure equals descends into the L</signature> |
130 | |
131 | =cut |
132 | |
133 | around 'equals' => sub { |
134 | my ($equals, $self, $compared_type_constraint) = @_; |
135 | |
136 | ## Make sure we are comparing typeconstraints of the same base class |
137 | return unless $compared_type_constraint->isa(__PACKAGE__); |
138 | |
139 | ## Make sure the base equals is also good |
140 | return unless $self->$equals($compared_type_constraint); |
141 | |
142 | ## Make sure the signatures match |
143 | return unless $self->signature_equals($compared_type_constraint); |
144 | |
145 | ## If we get this far, the two are equal |
146 | return 1; |
147 | }; |
148 | |
149 | =head2 signature_equals |
150 | |
151 | Check that the signature equals another signature. |
152 | |
153 | =cut |
154 | |
155 | sub signature_equals { |
156 | my ($self, $compared_type_constraint) = @_; |
157 | |
158 | foreach my $idx (keys %{$self->signature}) { |
159 | my $this = $self->signature->{$idx}; |
160 | my $that = $compared_type_constraint->signature->{$idx}; |
161 | return unless $this->equals($that); |
162 | } |
163 | |
164 | return 1; |
165 | } |
166 | |
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167 | =head1 AUTHOR |
168 | |
169 | John James Napiorkowski <jjnapiork@cpan.org> |
170 | |
171 | =head1 LICENSE |
172 | |
173 | You may distribute this code under the same terms as Perl itself. |
174 | |
175 | =cut |
176 | |
177 | no Moose; 1; |