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1 | package ## Hide from PAUSE |
2 | MooseX::Meta::TypeConstraint::Dependent; |
3 | |
4 | use Moose; |
5 | use Moose::Util::TypeConstraints (); |
6 | use MooseX::Meta::TypeCoercion::Dependent; |
7 | extends 'Moose::Meta::TypeConstraint'; |
8 | |
9 | =head1 NAME |
10 | |
11 | MooseX::Meta::TypeConstraint::Dependent - Metaclass for Dependent type constraints. |
12 | |
13 | =head1 DESCRIPTION |
14 | |
15 | see L<MooseX::Types::Dependent> for examples and details of how to use dependent |
16 | types. This class is a subclass of L<Moose::Meta::TypeConstraint> which |
17 | provides the gut functionality to enable dependent type constraints. |
18 | |
19 | =head1 ATTRIBUTES |
20 | |
21 | This class defines the following attributes. |
22 | |
23 | =head2 dependent_type_constraint |
24 | |
25 | The type constraint whose validity is being made dependent on a value that is a |
26 | L</constraining_type_constraint> |
27 | |
28 | =cut |
29 | |
30 | has 'dependent_type_constraint' => ( |
31 | is=>'ro', |
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32 | isa=>'Object', |
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33 | predicate=>'has_dependent_type_constraint', |
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34 | handles=>{ |
35 | check_dependent=>'check', |
36 | }, |
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37 | ); |
38 | |
39 | =head2 constraining_type_constraint |
40 | |
41 | This is a type constraint which defines what kind of value is allowed to be the |
42 | constraining value of the depending type. |
43 | |
44 | =cut |
45 | |
46 | has 'constraining_type_constraint' => ( |
47 | is=>'ro', |
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48 | isa=>'Object', |
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49 | predicate=>'has_constraining_type_constraint', |
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50 | handles=>{ |
51 | check_constraining=>'check', |
52 | }, |
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53 | ); |
54 | |
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55 | =head2 comparison_callback |
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56 | |
57 | This is a callback which returns a boolean value. It get's passed the value |
58 | L</constraining_type_constraint> validates as well as the check value. |
59 | |
60 | This callback is executed in addition to anything you put into a 'where' clause. |
61 | However, the 'where' clause only get's the check value. |
62 | |
63 | Exercise some sanity, this should be limited to actual comparision operations, |
64 | not as a sneaky way to mess with the constraining value. |
65 | |
66 | =cut |
67 | |
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68 | has 'comparison_callback' => ( |
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69 | is=>'ro', |
70 | isa=>'CodeRef', |
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71 | predicate=>'has_comparison_callback', |
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72 | ); |
73 | |
74 | =head2 constraint_generator |
75 | |
76 | A subref or closure that contains the way we validate incoming values against |
77 | a set of type constraints. |
78 | |
79 | =cut |
80 | |
81 | has 'constraint_generator' => ( |
82 | is=>'ro', |
83 | isa=>'CodeRef', |
84 | predicate=>'has_constraint_generator', |
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85 | required=>1, |
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86 | ); |
87 | |
88 | =head1 METHODS |
89 | |
90 | This class defines the following methods. |
91 | |
92 | =head2 new |
93 | |
94 | Initialization stuff. |
95 | |
96 | =cut |
97 | |
98 | around 'new' => sub { |
99 | my ($new, $class, @args) = @_; |
100 | my $self = $class->$new(@args); |
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101 | $self->coercion(MooseX::Meta::TypeCoercion::Dependent->new( |
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102 | type_constraint => $self, |
103 | )); |
104 | return $self; |
105 | }; |
106 | |
107 | =head2 generate_constraint_for ($type_constraints) |
108 | |
109 | Given some type constraints, use them to generate validation rules for an ref |
110 | of values (to be passed at check time) |
111 | |
112 | =cut |
113 | |
114 | sub generate_constraint_for { |
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115 | my ($self, $callback) = @_; |
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116 | return sub { |
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117 | my ($dependent_pair) = @_; |
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118 | my ($dependent, $constraining) = @$dependent_pair; |
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119 | |
120 | ## First need to test the bits |
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121 | unless($self->check_dependent($dependent)) { |
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122 | return; |
123 | } |
124 | |
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125 | unless($self->check_constraining($constraining)) { |
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126 | return; |
127 | } |
128 | |
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129 | my $constraint_generator = $self->constraint_generator; |
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130 | return $constraint_generator->( |
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131 | $dependent, |
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132 | $callback, |
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133 | $constraining, |
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134 | ); |
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135 | }; |
136 | } |
137 | |
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138 | =head2 parameterize ($dependent, $callback, $constraining) |
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139 | |
140 | Given a ref of type constraints, create a structured type. |
141 | |
142 | =cut |
143 | |
144 | sub parameterize { |
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145 | my ($self, $dependent_tc, $callback, $constraining_tc) = @_; |
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146 | my $class = ref $self; |
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147 | my $name = $self->_generate_subtype_name($dependent_tc, $callback, $constraining_tc); |
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148 | my $constraint_generator = $self->__infer_constraint_generator; |
149 | |
150 | return $class->new( |
151 | name => $name, |
152 | parent => $self, |
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153 | dependent_type_constraint=>$dependent_tc, |
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154 | comparison_callback=>$callback, |
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155 | constraint_generator => $constraint_generator, |
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156 | constraining_type_constraint => $constraining_tc, |
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157 | ); |
158 | } |
159 | |
160 | =head2 _generate_subtype_name |
161 | |
162 | Returns a name for the dependent type that should be unique |
163 | |
164 | =cut |
165 | |
166 | sub _generate_subtype_name { |
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167 | my ($self, $dependent_tc, $callback, $constraining_tc) = @_; |
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168 | return sprintf( |
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169 | "%s_depends_on_%s_via_%s", |
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170 | $dependent_tc, $constraining_tc, $callback, |
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171 | ); |
172 | } |
173 | |
174 | =head2 __infer_constraint_generator |
175 | |
176 | This returns a CODEREF which generates a suitable constraint generator. Not |
177 | user servicable, you'll never call this directly. |
178 | |
179 | TBD, this is definitely going to need some work. |
180 | |
181 | =cut |
182 | |
183 | sub __infer_constraint_generator { |
184 | my ($self) = @_; |
185 | if($self->has_constraint_generator) { |
186 | return $self->constraint_generator; |
187 | } else { |
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188 | warn "I'm doing the questioning infer generator thing"; |
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189 | return sub { |
190 | ## I'm not sure about this stuff but everything seems to work |
191 | my $tc = shift @_; |
192 | my $merged_tc = [ |
193 | @$tc, |
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194 | $self->comparison_callback, |
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195 | $self->constraining_type_constraint, |
196 | ]; |
197 | |
198 | $self->constraint->($merged_tc, @_); |
199 | }; |
200 | } |
201 | } |
202 | |
203 | =head2 compile_type_constraint |
204 | |
205 | hook into compile_type_constraint so we can set the correct validation rules. |
206 | |
207 | =cut |
208 | |
209 | around 'compile_type_constraint' => sub { |
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210 | my ($compile_type_constraint, $self) = @_; |
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211 | |
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212 | if($self->has_comparison_callback && |
213 | $self->has_constraining_type_constraint) { |
214 | my $generated_constraint = $self->generate_constraint_for( |
215 | $self->comparison_callback, |
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216 | ); |
217 | $self->_set_constraint($generated_constraint); |
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218 | } |
219 | |
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220 | return $self->$compile_type_constraint; |
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221 | }; |
222 | |
223 | =head2 create_child_type |
224 | |
225 | modifier to make sure we get the constraint_generator |
226 | |
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227 | =cut |
228 | |
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229 | around 'create_child_type' => sub { |
230 | my ($create_child_type, $self, %opts) = @_; |
231 | return $self->$create_child_type( |
232 | %opts, |
233 | constraint_generator => $self->__infer_constraint_generator, |
234 | ); |
235 | }; |
236 | |
237 | =head2 is_a_type_of |
238 | |
239 | =head2 is_subtype_of |
240 | |
241 | =head2 equals |
242 | |
243 | Override the base class behavior. |
244 | |
245 | TBD |
246 | |
247 | sub equals { |
248 | my ( $self, $type_or_name ) = @_; |
249 | my $other = Moose::Util::TypeConstraints::find_type_constraint($type_or_name); |
250 | |
251 | return unless $other->isa(__PACKAGE__); |
252 | |
253 | return ( |
254 | $self->type_constraints_equals($other) |
255 | and |
256 | $self->parent->equals( $other->parent ) |
257 | ); |
258 | } |
259 | |
260 | =head2 type_constraints_equals |
261 | |
262 | Checks to see if the internal type contraints are equal. |
263 | |
264 | TBD |
265 | |
266 | sub type_constraints_equals { |
267 | my ($self, $other) = @_; |
268 | my @self_type_constraints = @{$self->type_constraints||[]}; |
269 | my @other_type_constraints = @{$other->type_constraints||[]}; |
270 | |
271 | ## Incoming ay be either arrayref or hashref, need top compare both |
272 | while(@self_type_constraints) { |
273 | my $self_type_constraint = shift @self_type_constraints; |
274 | my $other_type_constraint = shift @other_type_constraints |
275 | || return; ## $other needs the same number of children. |
276 | |
277 | if( ref $self_type_constraint) { |
278 | $self_type_constraint->equals($other_type_constraint) |
279 | || return; ## type constraints obviously need top be equal |
280 | } else { |
281 | $self_type_constraint eq $other_type_constraint |
282 | || return; ## strings should be equal |
283 | } |
284 | |
285 | } |
286 | |
287 | return 1; ##If we get this far, everything is good. |
288 | } |
289 | |
290 | =head2 get_message |
291 | |
292 | Give you a better peek into what's causing the error. For now we stringify the |
293 | incoming deep value with L<Devel::PartialDump> and pass that on to either your |
294 | custom error message or the default one. In the future we'll try to provide a |
295 | more complete stack trace of the actual offending elements |
296 | |
297 | TBD |
298 | |
299 | around 'get_message' => sub { |
300 | my ($get_message, $self, $value) = @_; |
301 | my $new_value = Devel::PartialDump::dump($value); |
302 | return $self->$get_message($new_value); |
303 | }; |
304 | |
305 | =head1 SEE ALSO |
306 | |
307 | The following modules or resources may be of interest. |
308 | |
309 | L<Moose>, L<Moose::Meta::TypeConstraint> |
310 | |
311 | =head1 AUTHOR |
312 | |
313 | John Napiorkowski, C<< <jjnapiork@cpan.org> >> |
314 | |
315 | =head1 COPYRIGHT & LICENSE |
316 | |
317 | This program is free software; you can redistribute it and/or modify |
318 | it under the same terms as Perl itself. |
319 | |
320 | =cut |
321 | |
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322 | __PACKAGE__->meta->make_immutable; |