NAME

       Moose::Meta::TypeConstraint - The Moose Type Constraint metaclass

VERSION

       version 2.2009

DESCRIPTION

       This class represents a single type constraint. Moose's built-in type constraints, as well
       as constraints you define, are all stored in a Moose::Meta::TypeConstraint::Registry
       object as objects of this class.

INHERITANCE

       "Moose::Meta::TypeConstraint" is a subclass of Class::MOP::Object.

METHODS

   Moose::Meta::TypeConstraint->new(%options)
       This creates a new type constraint based on the provided %options:

       •   name

           The constraint name. If a name is not provided, it will be set to "__ANON__".

       •   parent

           A "Moose::Meta::TypeConstraint" object which is the parent type for the type being
           created. This is optional.

       •   constraint

           This is the subroutine reference that implements the actual constraint check. This
           defaults to a subroutine which always returns true.

       •   message

           A subroutine reference which is used to generate an error message when the constraint
           fails. This is optional.

       •   coercion

           A Moose::Meta::TypeCoercion object representing the coercions to the type. This is
           optional.

       •   inlined

           A subroutine which returns a string suitable for inlining this type constraint. It
           will be called as a method on the type constraint object, and will receive a single
           additional parameter, a variable name to be tested (usually "$_" or "$_[0]".

           This is optional.

       •   inline_environment

           A hash reference of variables to close over. The keys are variables names, and the
           values are references to the variables.

   $constraint->equals($type_name_or_object)
       Returns true if the supplied name or type object is the same as the current type.

   $constraint->is_subtype_of($type_name_or_object)
       Returns true if the supplied name or type object is a parent of the current type.

   $constraint->is_a_type_of($type_name_or_object)
       Returns true if the given type is the same as the current type, or is a parent of the
       current type. This is a shortcut for checking "equals" and "is_subtype_of".

   $constraint->coerce($value)
       This will attempt to coerce the value to the type. If the type does not have any defined
       coercions this will throw an error.

       If no coercion can produce a value matching $constraint, the original value is returned.

   $constraint->assert_coerce($value)
       This method behaves just like "coerce", but if the result is not valid according to
       $constraint, an error is thrown.

   $constraint->check($value)
       Returns true if the given value passes the constraint for the type.

   $constraint->validate($value)
       This is similar to "check". However, if the type is valid then the method returns an
       explicit "undef". If the type is not valid, we call "$self->get_message($value)"
       internally to generate an error message.

   $constraint->assert_valid($value)
       Like "check" and "validate", this method checks whether $value is valid under the
       constraint.  If it is, it will return true.  If it is not, an exception will be thrown
       with the results of "$self->get_message($value)".

   $constraint->name
       Returns the type's name, as provided to the constructor.

   $constraint->parent
       Returns the type's parent, as provided to the constructor, if any.

   $constraint->has_parent
       Returns true if the type has a parent type.

   $constraint->parents
       Returns all of the types parents as an list of type constraint objects.

   $constraint->constraint
       Returns the type's constraint, as provided to the constructor.

   $constraint->get_message($value)
       This generates a method for the given value. If the type does not have an explicit
       message, we generate a default message.

   $constraint->has_message
       Returns true if the type has a message.

   $constraint->message
       Returns the type's message as a subroutine reference.

   $constraint->coercion
       Returns the type's Moose::Meta::TypeCoercion object, if one exists.

   $constraint->has_coercion
       Returns true if the type has a coercion.

   $constraint->can_be_inlined
       Returns true if this type constraint can be inlined. A type constraint which subtypes an
       inlinable constraint and does not add an additional constraint "inherits" its parent
       type's inlining.

   $constraint->create_child_type(%options)
       This returns a new type constraint of the same class using the provided %options. The
       "parent" option will be the current type.

       This method exists so that subclasses of this class can override this behavior and change
       how child types are created.

BUGS

       See "BUGS" in Moose for details on reporting bugs.

AUTHORS

       •   Stevan Little <stevan.little@iinteractive.com>

       •   Dave Rolsky <autarch@urth.org>

       •   Jesse Luehrs <doy@tozt.net>

       •   Shawn M Moore <code@sartak.org>

       •   יובל קוג'מן (Yuval Kogman) <nothingmuch@woobling.org>

       •   Karen Etheridge <ether@cpan.org>

       •   Florian Ragwitz <rafl@debian.org>

       •   Hans Dieter Pearcey <hdp@weftsoar.net>

       •   Chris Prather <chris@prather.org>

       •   Matt S Trout <mst@shadowcat.co.uk>

COPYRIGHT AND LICENSE

       This software is copyright (c) 2006 by Infinity Interactive, Inc.

       This is free software; you can redistribute it and/or modify it under the same terms as
       the Perl 5 programming language system itself.