1 package ## Hide from PAUSE
2 MooseX::Meta::TypeConstraint::Dependent;
5 use Moose::Util::TypeConstraints ();
6 use MooseX::Meta::TypeCoercion::Dependent;
7 extends 'Moose::Meta::TypeConstraint';
11 MooseX::Meta::TypeConstraint::Dependent - Metaclass for Dependent type constraints.
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.
21 This class defines the following attributes.
23 =head2 dependent_type_constraint
25 The type constraint whose validity is being made dependent on a value that is a
26 L</constraining_type_constraint>
30 has 'dependent_type_constraint' => (
33 predicate=>'has_dependent_type_constraint',
35 check_dependent=>'check',
39 =head2 constraining_type_constraint
41 This is a type constraint which defines what kind of value is allowed to be the
42 constraining value of the depending type.
46 has 'constraining_type_constraint' => (
49 predicate=>'has_constraining_type_constraint',
51 check_constraining=>'check',
55 =head2 comparison_callback
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.
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.
63 Exercise some sanity, this should be limited to actual comparision operations,
64 not as a sneaky way to mess with the constraining value.
66 This should return a Bool, suitable for ->check (That is true for valid, false
71 has 'comparison_callback' => (
74 predicate=>'has_comparison_callback',
77 =head2 constraint_generator
79 A subref or closure that contains the way we validate incoming values against
80 a set of type constraints.
84 has 'constraint_generator' => (
87 predicate=>'has_constraint_generator',
93 This class defines the following methods.
101 around 'new' => sub {
102 my ($new, $class, @args) = @_;
103 my $self = $class->$new(@args);
104 $self->coercion(MooseX::Meta::TypeCoercion::Dependent->new(
105 type_constraint => $self,
110 =head2 generate_constraint_for ($type_constraints)
112 Given some type constraints, use them to generate validation rules for an ref
113 of values (to be passed at check time)
117 sub generate_constraint_for {
118 my ($self, $callback) = @_;
120 my ($dependent_pair) = @_;
121 my ($dependent, $constraining) = @$dependent_pair;
123 ## First need to test the bits
124 unless($self->check_dependent($dependent)) {
128 unless($self->check_constraining($constraining)) {
132 my $constraint_generator = $self->constraint_generator;
133 return $constraint_generator->(
141 =head2 parameterize ($dependent, $callback, $constraining)
143 Given a ref of type constraints, create a structured type.
148 my ($self, $dependent_tc, $callback, $constraining_tc) = @_;
149 my $class = ref $self;
150 my $name = $self->_generate_subtype_name($dependent_tc, $callback, $constraining_tc);
151 my $constraint_generator = $self->__infer_constraint_generator;
156 dependent_type_constraint=>$dependent_tc,
157 comparison_callback=>$callback,
158 constraint_generator => $constraint_generator,
159 constraining_type_constraint => $constraining_tc,
163 =head2 _generate_subtype_name
165 Returns a name for the dependent type that should be unique
169 sub _generate_subtype_name {
170 my ($self, $dependent_tc, $callback, $constraining_tc) = @_;
172 "%s_depends_on_%s_via_%s",
173 $dependent_tc, $constraining_tc, $callback,
177 =head2 __infer_constraint_generator
179 This returns a CODEREF which generates a suitable constraint generator. Not
180 user servicable, you'll never call this directly.
182 TBD, this is definitely going to need some work.
186 sub __infer_constraint_generator {
188 if($self->has_constraint_generator) {
189 return $self->constraint_generator;
191 warn "I'm doing the questioning infer generator thing";
193 ## I'm not sure about this stuff but everything seems to work
197 $self->comparison_callback,
198 $self->constraining_type_constraint,
201 $self->constraint->($merged_tc, @_);
206 =head2 compile_type_constraint
208 hook into compile_type_constraint so we can set the correct validation rules.
212 around 'compile_type_constraint' => sub {
213 my ($compile_type_constraint, $self) = @_;
215 if($self->has_comparison_callback &&
216 $self->has_constraining_type_constraint) {
217 my $generated_constraint = $self->generate_constraint_for(
218 $self->comparison_callback,
220 $self->_set_constraint($generated_constraint);
223 return $self->$compile_type_constraint;
226 =head2 create_child_type
228 modifier to make sure we get the constraint_generator
232 around 'create_child_type' => sub {
233 my ($create_child_type, $self, %opts) = @_;
234 return $self->$create_child_type(
236 constraint_generator => $self->__infer_constraint_generator,
246 Override the base class behavior.
251 my ( $self, $type_or_name ) = @_;
252 my $other = Moose::Util::TypeConstraints::find_type_constraint($type_or_name);
254 return unless $other->isa(__PACKAGE__);
257 $self->type_constraints_equals($other)
259 $self->parent->equals( $other->parent )
263 =head2 type_constraints_equals
265 Checks to see if the internal type contraints are equal.
269 sub type_constraints_equals {
270 my ($self, $other) = @_;
271 my @self_type_constraints = @{$self->type_constraints||[]};
272 my @other_type_constraints = @{$other->type_constraints||[]};
274 ## Incoming ay be either arrayref or hashref, need top compare both
275 while(@self_type_constraints) {
276 my $self_type_constraint = shift @self_type_constraints;
277 my $other_type_constraint = shift @other_type_constraints
278 || return; ## $other needs the same number of children.
280 if( ref $self_type_constraint) {
281 $self_type_constraint->equals($other_type_constraint)
282 || return; ## type constraints obviously need top be equal
284 $self_type_constraint eq $other_type_constraint
285 || return; ## strings should be equal
290 return 1; ##If we get this far, everything is good.
295 Give you a better peek into what's causing the error. For now we stringify the
296 incoming deep value with L<Devel::PartialDump> and pass that on to either your
297 custom error message or the default one. In the future we'll try to provide a
298 more complete stack trace of the actual offending elements
302 around 'get_message' => sub {
303 my ($get_message, $self, $value) = @_;
304 my $new_value = Devel::PartialDump::dump($value);
305 return $self->$get_message($new_value);
310 The following modules or resources may be of interest.
312 L<Moose>, L<Moose::Meta::TypeConstraint>
316 John Napiorkowski, C<< <jjnapiork@cpan.org> >>
318 =head1 COPYRIGHT & LICENSE
320 This program is free software; you can redistribute it and/or modify
321 it under the same terms as Perl itself.
325 __PACKAGE__->meta->make_immutable;