From: Dave Rolsky Date: Fri, 20 Mar 2009 20:02:32 +0000 (-0500) Subject: doc revamp for MM::Attribute X-Git-Tag: 0.72_01~63^2^2 X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=93a708fdd3c0fb148b8c05f272e6e43c8be46647;p=gitmo%2FMoose.git doc revamp for MM::Attribute --- diff --git a/lib/Moose/Meta/Attribute.pm b/lib/Moose/Meta/Attribute.pm index e487ca3..c88dbae 100644 --- a/lib/Moose/Meta/Attribute.pm +++ b/lib/Moose/Meta/Attribute.pm @@ -749,43 +749,145 @@ Moose::Meta::Attribute - The Moose attribute metaclass =head1 DESCRIPTION -This is a subclass of L with Moose specific -extensions. +This class is a subclass of L that provides +additional Moose-specific functionality. -For the most part, the only time you will ever encounter an -instance of this class is if you are doing some serious deep -introspection. To really understand this class, you need to refer -to the L documentation. +To really understand this class, you will probably need to start with +the L documentation. This class can be +understood as a set of additional features on top of the basic feature +provided by that parent class. =head1 METHODS -=head2 Overridden methods +Many of the documented below override methods in +L and add Moose specific features. -These methods override methods in L and add -Moose specific features. You can safely assume though that they -will behave just as L does. +=head2 Creation =over 4 -=item B +=item B<< Moose::Meta::Attribute->new(%options) >> -=item B +This method overrides the L constructor. -=item B +Many of the options below are described in more detail in the +L document. -=item B +It adds the following options to the constructor: -=item B +=over 8 -=item B +=item * is => 'ro' or 'rw' -=item B +This provides a shorthand for specifying the C, C, or +C names. If the attribute is read-only ('ro') then it will +have a C method with the same attribute as the name. -=item B +If it is read-write ('rw') then it will have an C method +with the same name. If you provide an explicit C for a +read-write attribute, then you will have a C with the same +name as the attribute, and a C with the name you provided. -=item B +=item * isa => $type -=item B +This option accepts a type. The type can be a string, which should be +a type name. If the type name is unknown, it is assumed to be a class +name. + +This option can also accept a L object. + +If you I provide a C option, then your C option must +be a class name, and that class must do the role specified with +C. + +=item * does => $role + +This is short-hand for saying that the attribute's type must be an +object which does the named role. + +=item * coerce => $bool + +This option is only valid for objects with a type constraint +(C). If this is true, then coercions will be applied whenever +this attribute is set. + +You can make both this and the C option true. + +=item * trigger => $sub + +This option accepts a subroutine reference, which will be called after +the attribute is set. + +=item * required => $bool + +An attribute which is required must be provided to the constructor. An +attribute which is required can also have a C or C, +which will satisy its required-ness. + +A required attribute must have a C, C or a +non-C C + +=item * lazy => $bool + +A lazy attribute must have a C or C. When an +attribute is lazy, the default value will not be calculated until the +attribute is read. + +=item * weak_ref => $bool + +If this is true, the attribute's value will be stored as a weak +reference. + +=item * auto_deref => $bool + +If this is true, then the reader will dereference the value when it is +called. The attribute must have a type constraint which defines the +attribute as an array or hash reference. + +=item * lazy_build => $bool + +Setting this to true makes the attribute lazy and provides a number of +default methods. + + has 'size' => ( + is => 'ro', + lazy_build => 1, + ); + +is equivalent to this: + + has 'size' => ( + is => 'ro', + lazy => 1, + builder => '_build_size', + clearer => 'clear_size', + predicate => 'has_size', + ); + +=item * documentation + +An arbitrary string that can be retrieved later by calling C<< +$attr->documentation >>. + +=back + +=item B<< $attr->clone(%options) >> + +This creates a new attribute based on attribute being cloned. You must +supply a C option to provide a new name for the attribute. + +The C<%options> can only specify options handled by +L. + +=head2 Value management + +=item B<< $attr->initialize_instance_slot($meta_instance, $instance, $params) >> + +This method is used internally to initialize the attribute's slot in +the object C<$instance>. + +This overrides the L method to handle lazy +attributes, weak references, and type constraints. =item B @@ -812,141 +914,161 @@ for an example. =back -=head2 Additional Moose features - -Moose attributes support type-constraint checking, weak reference -creation and type coercion. +=head2 Attribute Accessor generation =over 4 -=item B +=item B<< $attr->install_accessors >> -Delegates to C or C if there is none. +This method overrides the parent to also install delegation methods. -=item B +=item B<< $attr->remove_accessors>> -=item B +This method overrides the parent to also remove delegation methods. -When called as a class method causes interpretation of the C and -C options. +=item B<< $attr->install_delegation >> + +This method adds its delegation methods to the attribute's associated +class, if it has any to add. + +=item B<< $attr->remove_delegation >> + +This method remove its delegation methods from the attribute's +associated class. -=item B +=item B<< $attr->accessor_metaclass >> -This is to support the C feature, it clones an attribute -from a superclass and allows a very specific set of changes to be made -to the attribute. +Returns the accessor metaclass name, which defaults to +L. + +=item B<< $attr->delegation_metaclass >> + +Returns the delegation metaclass name, which defaults to +L. + +=back + +=head2 Additional Moose features + +These methods are not found in the superclass. They support features +provided by Moose. + +=item B<< $attr->does($role) >> + +This indicates whether the I does the given +role. The role can be given as a full class name, or as a resolveable +trait name. + +Note that this checks the attribute itself, not its type constraint, +so it is checking the attribute's metaclass and any traits applied to +the attribute. + +=item B<< Moose::Meta::Class->interpolate_class_and_new($name, %options) >> + +This is an alternate constructor that handles the C and +C options. -=item B +Effectively, this method is a factory that finds or creates the +appropriate class for the given C and/or Cnew($name, +%options) >> on that class. -=item B +=item B<< $attr->clone_and_inherit_options(%options) >> -Returns true if this meta-attribute has a type constraint. +This method supports the C feature. It does various bits +of processing on the supplied C<%options> before ultimately calling +the C method. -=item B +One of its main tasks is to make sure that the C<%options> provided +only includes the options returned by the +C method. -A read-only accessor for this meta-attribute's type constraint. For -more information on what you can do with this, see the documentation -for L. +=item B<< $attr->legal_options_for_inheritance >> -=item B +This returns a whitelist of options that can be overridden in a +subclass's attribute definition. -Verifies that the given value is valid under this attribute's type -constraint, otherwise throws an error. +This exists to allow a custom metaclass to change or add to the list +of options which can be changed. -=item B +=item B<< $attr->type_constraint >> -Returns true if this meta-attribute performs delegation. +Returns the L object for this attribute, +if it has one. -=item B +=item B<< $attr->has_type_constraint >> -This returns the value which was passed into the handles option. +Returns true if this attribute has a type constraint. -=item B +=item B<< $attr->verify_against_type_constraint($value) >> -Returns true if this meta-attribute produces a weak reference. +Given a value, this method returns true if the value is valid for the +attribute's type constraint. If the value is not valid, it throws an +error. -=item B +=item B<< $attr->handles >> -Returns true if this meta-attribute is required to have a value. +This returns the value of the C option passed to the +constructor. -=item B +=item B<< $attr->has_handles >> -Returns true if this meta-attribute should be initialized lazily. +Returns true if this attribute performs delegation. -NOTE: lazy attributes, B have a C or C field set. +=item B<< $attr->is_weak_ref >> -=item B +Returns true if this attribute stores its value as a weak reference. -Returns true if this meta-attribute should be initialized lazily through -the builder generated by lazy_build. Using C 1> will -make your attribute required and lazy. In addition it will set the builder, clearer -and predicate options for you using the following convention. +=item B<< $attr->is_required >> - #If your attribute name starts with an underscore: - has '_foo' => (lazy_build => 1); - #is the same as - has '_foo' => (lazy => 1, required => 1, predicate => '_has_foo', clearer => '_clear_foo', builder => '_build__foo'); - # or - has '_foo' => (lazy => 1, required => 1, predicate => '_has_foo', clearer => '_clear_foo', default => sub{shift->_build__foo}); +Returns true if this attribute is required to have a value. - #If your attribute name does not start with an underscore: - has 'foo' => (lazy_build => 1); - #is the same as - has 'foo' => (lazy => 1, required => 1, predicate => 'has_foo', clearer => 'clear_foo', builder => '_build_foo'); - # or - has 'foo' => (lazy => 1, required => 1, predicate => 'has_foo', clearer => 'clear_foo', default => sub{shift->_build_foo}); +=item B<< $attr->is_lazy >> -The reason for the different naming of the C is that the C -method is a private method while the C and C methods -are public methods. +Returns true if this attribute is lazy. -NOTE: This means your class should provide a method whose name matches the value -of the builder part, in this case _build__foo or _build_foo. +=item B<< $attr->is_lazy_build >> -=item B +Returns true if the C option was true when passed to the +constructor. -Returns true if this meta-attribute should perform type coercion. +=item B<< $attr->should_coerce >> -=item B +Returns true if the C option passed to the constructor was +true. -Returns true if this meta-attribute should perform automatic -auto-dereferencing. +=item B<< $attr->should_auto_deref >> -NOTE: This can only be done for attributes whose type constraint is -either I or I. +Returns true if the C option passed to the constructor was +true. -=item B +=item B<< $attr->trigger >> -Returns true if this meta-attribute has a trigger set. +This is the subroutine reference that was in the C option +passed to the constructor, if any. -=item B +=item B<< $attr->has_trigger>> -This is a CODE reference which will be executed every time the -value of an attribute is assigned. The CODE ref will get two values, -the invocant and the new value. This can be used to handle I -bi-directional relations. +Returns true if this attribute has a trigger set. -=item B +=item B<< $attr->documentation >> -This is a string which contains the documentation for this attribute. -It serves no direct purpose right now, but it might in the future -in some kind of automated documentation system perhaps. +Returns the value that was in the C option passed to +the constructor, if any. -=item B +=item B<< $attr->has_documentation >> -Returns true if this meta-attribute has any documentation. +Returns true if this attribute has any documentation. -=item B +=item B<< $attr->applied_traits >> -This will return the ARRAY ref of all the traits applied to this -attribute, or if no traits have been applied, it returns C. +This returns an array reference of all the traits which were applied +to this attribute. If none were applied, this returns C. -=item B +=item B<< $attr->has_applied_traits >> -Returns true if this meta-attribute has any traits applied. +Returns true if this attribute has any traits applied. =back diff --git a/xt/pod_coverage.t b/xt/pod_coverage.t index 21c274a..8e15c61 100644 --- a/xt/pod_coverage.t +++ b/xt/pod_coverage.t @@ -14,7 +14,8 @@ my @modules = all_modules(); plan tests => scalar @modules; my %trustme = ( - 'Moose' => ['make_immutable'], + 'Moose' => ['make_immutable'], + 'Moose::Meta::Attribute' => [ 'interpolate_class', 'throw_error' ], 'Moose::Meta::Method::Constructor' => [qw( initialize_body intialize_body)], 'Moose::Meta::Method::Destructor' => ['initialize_body'],