1Moose::Meta::TypeConstrUasienrt(C3o)ntributed Perl DocumMeonotsaet:i:oMneta::TypeConstraint(3)
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6 Moose::Meta::TypeConstraint - The Moose Type Constraint metaclass
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9 version 2.2015
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12 This class represents a single type constraint. Moose's built-in type
13 constraints, as well as constraints you define, are all stored in a
14 Moose::Meta::TypeConstraint::Registry object as objects of this class.
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17 "Moose::Meta::TypeConstraint" is a subclass of Class::MOP::Object.
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20 Moose::Meta::TypeConstraint->new(%options)
21 This creates a new type constraint based on the provided %options:
22 • name
24 The constraint name. If a name is not provided, it will be set to
26 "__ANON__".
27 • parent
29 A "Moose::Meta::TypeConstraint" object which is the parent type for
31 the type being created. This is optional.
32 • constraint
34 This is the subroutine reference that implements the actual
36 constraint check. This defaults to a subroutine which always
37 returns true.
38 • message
40 A subroutine reference which is used to generate an error message
42 when the constraint fails. This is optional.
43 • coercion
45 A Moose::Meta::TypeCoercion object representing the coercions to
47 the type. This is optional.
48 • inlined
50 A subroutine which returns a string suitable for inlining this type
52 constraint. It will be called as a method on the type constraint
53 object, and will receive a single additional parameter, a variable
54 name to be tested (usually "$_" or "$_[0]".
55 This is optional.
57 • inline_environment
59 A hash reference of variables to close over. The keys are variables
61 names, and the values are references to the variables.
62 $constraint->equals($type_name_or_object)
64 Returns true if the supplied name or type object is the same as the
65 current type.
66 $constraint->is_subtype_of($type_name_or_object)
68 Returns true if the supplied name or type object is a parent of the
69 current type.
70 $constraint->is_a_type_of($type_name_or_object)
72 Returns true if the given type is the same as the current type, or is a
73 parent of the current type. This is a shortcut for checking "equals"
74 and "is_subtype_of".
75 $constraint->coerce($value)
77 This will attempt to coerce the value to the type. If the type does not
78 have any defined coercions this will throw an error.
79 If no coercion can produce a value matching $constraint, the original
81 value is returned.
82 $constraint->assert_coerce($value)
84 This method behaves just like "coerce", but if the result is not valid
85 according to $constraint, an error is thrown.
86 $constraint->check($value)
88 Returns true if the given value passes the constraint for the type.
89 $constraint->validate($value)
91 This is similar to "check". However, if the type is valid then the
92 method returns an explicit "undef". If the type is not valid, we call
93 "$self->get_message($value)" internally to generate an error message.
94 $constraint->assert_valid($value)
96 Like "check" and "validate", this method checks whether $value is valid
97 under the constraint. If it is, it will return true. If it is not, an
98 exception will be thrown with the results of
99 "$self->get_message($value)".
100 $constraint->name
102 Returns the type's name, as provided to the constructor.
103 $constraint->parent
105 Returns the type's parent, as provided to the constructor, if any.
106 $constraint->has_parent
108 Returns true if the type has a parent type.
109 $constraint->parents
111 Returns all of the types parents as an list of type constraint objects.
112 $constraint->constraint
114 Returns the type's constraint, as provided to the constructor.
115 $constraint->get_message($value)
117 This generates a method for the given value. If the type does not have
118 an explicit message, we generate a default message.
119 $constraint->has_message
121 Returns true if the type has a message.
122 $constraint->message
124 Returns the type's message as a subroutine reference.
125 $constraint->coercion
127 Returns the type's Moose::Meta::TypeCoercion object, if one exists.
128 $constraint->has_coercion
130 Returns true if the type has a coercion.
131 $constraint->can_be_inlined
133 Returns true if this type constraint can be inlined. A type constraint
134 which subtypes an inlinable constraint and does not add an additional
135 constraint "inherits" its parent type's inlining.
136 $constraint->create_child_type(%options)
138 This returns a new type constraint of the same class using the provided
139 %options. The "parent" option will be the current type.
140 This method exists so that subclasses of this class can override this
142 behavior and change how child types are created.
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145 See "BUGS" in Moose for details on reporting bugs.
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148 • Stevan Little <stevan@cpan.org>
149 • Dave Rolsky <autarch@urth.org>
151 • Jesse Luehrs <doy@cpan.org>
153 • Shawn M Moore <sartak@cpan.org>
155 • יובל קוג'מן (Yuval Kogman) <nothingmuch@woobling.org>
157 • Karen Etheridge <ether@cpan.org>
159 • Florian Ragwitz <rafl@debian.org>
161 • Hans Dieter Pearcey <hdp@cpan.org>
163 • Chris Prather <chris@prather.org>
165 • Matt S Trout <mstrout@cpan.org>
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169 This software is copyright (c) 2006 by Infinity Interactive, Inc.
170 This is free software; you can redistribute it and/or modify it under
172 the same terms as the Perl 5 programming language system itself.
173perl v5.34.0 2021-07-22 Moose::Meta::TypeConstraint(3)