X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FMoose%2FMeta%2FAttribute.pm;h=0bd227adb3d02a5dc4476e41746d185f0c3c139d;hb=d5c30e5273a24e66bc3028d8a63e1e07aeaa2d58;hp=d00d6ffe729f0d793fe506a462fe3e4def0c85e3;hpb=d022f632fd6a270c5a76667a2c2b50ae367ed359;p=gitmo%2FMoose.git diff --git a/lib/Moose/Meta/Attribute.pm b/lib/Moose/Meta/Attribute.pm index d00d6ff..0bd227a 100644 --- a/lib/Moose/Meta/Attribute.pm +++ b/lib/Moose/Meta/Attribute.pm @@ -6,11 +6,14 @@ use warnings; use Scalar::Util 'blessed', 'weaken', 'reftype'; use Carp 'confess'; +use Sub::Name 'subname'; +use overload (); -our $VERSION = '0.10'; +our $VERSION = '0.22'; our $AUTHORITY = 'cpan:STEVAN'; use Moose::Meta::Method::Accessor; +use Moose::Util (); use Moose::Util::TypeConstraints (); use base 'Class::MOP::Attribute'; @@ -24,6 +27,7 @@ __PACKAGE__->meta->add_attribute('is' => (reader => '_is_metadata')); # these are actual options for the attrs __PACKAGE__->meta->add_attribute('required' => (reader => 'is_required' )); __PACKAGE__->meta->add_attribute('lazy' => (reader => 'is_lazy' )); +__PACKAGE__->meta->add_attribute('lazy_build' => (reader => 'is_lazy_build' )); __PACKAGE__->meta->add_attribute('coerce' => (reader => 'should_coerce' )); __PACKAGE__->meta->add_attribute('weak_ref' => (reader => 'is_weak_ref' )); __PACKAGE__->meta->add_attribute('auto_deref' => (reader => 'should_auto_deref')); @@ -39,151 +43,197 @@ __PACKAGE__->meta->add_attribute('handles' => ( reader => 'handles', predicate => 'has_handles', )); +__PACKAGE__->meta->add_attribute('documentation' => ( + reader => 'documentation', + predicate => 'has_documentation', +)); +__PACKAGE__->meta->add_attribute('traits' => ( + reader => 'applied_traits', + predicate => 'has_applied_traits', +)); + +# NOTE: +# we need to have a ->does method in here to +# more easily support traits, and the introspection +# of those traits. So in order to do this we +# just alias Moose::Object's version of it. +# - SL +*does = \&Moose::Object::does; sub new { - my ($class, $name, %options) = @_; - $class->_process_options($name, \%options); - return $class->SUPER::new($name, %options); + my ($class, $name, %options) = @_; + $class->_process_options($name, \%options); + return $class->SUPER::new($name, %options); +} + +sub interpolate_class_and_new { + my ($class, $name, @args) = @_; + + $class->interpolate_class(@args)->new($name, @args); +} + +sub interpolate_class { + my ($class, %options) = @_; + + if ( my $metaclass_name = $options{metaclass} ) { + $class = Moose::Util::resolve_metaclass_alias( Attribute => $metaclass_name ); + } + + if (my $traits = $options{traits}) { + my @traits = map { + Moose::Util::resolve_metatrait_alias( Attribute => $_ ) + or + $_ + } @$traits; + + my $anon_class = Moose::Meta::Class->create_anon_class( + superclasses => [ $class ], + roles => [ @traits ], + cache => 1, + ); + + return $anon_class->name; + } + else { + return $class; + } } sub clone_and_inherit_options { my ($self, %options) = @_; - # you can change default, required and coerce + # you can change default, required, coerce, documentation, lazy, handles, builder, metaclass and traits my %actual_options; - foreach my $legal_option (qw(default coerce required)) { + foreach my $legal_option (qw(default coerce required documentation lazy handles builder metaclass traits)) { if (exists $options{$legal_option}) { $actual_options{$legal_option} = $options{$legal_option}; delete $options{$legal_option}; } } - # isa can be changed, but only if the - # new type is a subtype + if ($options{isa}) { my $type_constraint; - if (blessed($options{isa}) && $options{isa}->isa('Moose::Meta::TypeConstraint')) { - $type_constraint = $options{isa}; - } - else { - $type_constraint = Moose::Util::TypeConstraints::find_type_constraint($options{isa}); - (defined $type_constraint) - || confess "Could not find the type constraint '" . $options{isa} . "'"; - } - # NOTE: - # check here to see if the new type - # is a subtype of the old one - ($type_constraint->is_subtype_of($self->type_constraint->name)) - || confess "New type constraint setting must be a subtype of inherited one" - # iff we have a type constraint that is ... - if $self->has_type_constraint; - # then we use it :) - $actual_options{type_constraint} = $type_constraint; + if (blessed($options{isa}) && $options{isa}->isa('Moose::Meta::TypeConstraint')) { + $type_constraint = $options{isa}; + } + else { + $type_constraint = Moose::Util::TypeConstraints::find_or_create_isa_type_constraint($options{isa}); + (defined $type_constraint) + || confess "Could not find the type constraint '" . $options{isa} . "'"; + } + + $actual_options{type_constraint} = $type_constraint; delete $options{isa}; } - (scalar keys %options == 0) + + if ($options{does}) { + my $type_constraint; + if (blessed($options{does}) && $options{does}->isa('Moose::Meta::TypeConstraint')) { + $type_constraint = $options{does}; + } + else { + $type_constraint = Moose::Util::TypeConstraints::find_or_create_does_type_constraint($options{does}); + (defined $type_constraint) + || confess "Could not find the type constraint '" . $options{does} . "'"; + } + + $actual_options{type_constraint} = $type_constraint; + delete $options{does}; + } + + (scalar keys %options == 0) || confess "Illegal inherited options => (" . (join ', ' => keys %options) . ")"; $self->clone(%actual_options); } sub _process_options { my ($class, $name, $options) = @_; - - if (exists $options->{is}) { - if ($options->{is} eq 'ro') { - $options->{reader} = $name; - (!exists $options->{trigger}) - || confess "Cannot have a trigger on a read-only attribute"; - } - elsif ($options->{is} eq 'rw') { - $options->{accessor} = $name; - ((reftype($options->{trigger}) || '') eq 'CODE') - || confess "Trigger must be a CODE ref" - if exists $options->{trigger}; - } - else { - confess "I do not understand this option (is => " . $options->{is} . ")" - } - } - - if (exists $options->{isa}) { - - if (exists $options->{does}) { - if (eval { $options->{isa}->can('does') }) { - ($options->{isa}->does($options->{does})) - || confess "Cannot have an isa option and a does option if the isa does not do the does"; - } - else { - confess "Cannot have an isa option which cannot ->does()"; - } - } - - # allow for anon-subtypes here ... - if (blessed($options->{isa}) && $options->{isa}->isa('Moose::Meta::TypeConstraint')) { - $options->{type_constraint} = $options->{isa}; - } - else { - - if ($options->{isa} =~ /\|/) { - my @type_constraints = split /\s*\|\s*/ => $options->{isa}; - $options->{type_constraint} = Moose::Util::TypeConstraints::create_type_constraint_union( - @type_constraints - ); - } - else { - # otherwise assume it is a constraint - my $constraint = Moose::Util::TypeConstraints::find_type_constraint($options->{isa}); - # if the constraing it not found .... - unless (defined $constraint) { - # assume it is a foreign class, and make - # an anon constraint for it - $constraint = Moose::Util::TypeConstraints::subtype( - 'Object', - Moose::Util::TypeConstraints::where { $_->isa($options->{isa}) } - ); - } - $options->{type_constraint} = $constraint; + + if (exists $options->{is}) { + if ($options->{is} eq 'ro') { + $options->{reader} ||= $name; + (!exists $options->{trigger}) + || confess "Cannot have a trigger on a read-only attribute $name"; + } + elsif ($options->{is} eq 'rw') { + $options->{accessor} = $name; + ((reftype($options->{trigger}) || '') eq 'CODE') + || confess "Trigger must be a CODE ref" + if exists $options->{trigger}; + } + else { + confess "I do not understand this option (is => " . $options->{is} . ") on attribute $name" + } + } + + if (exists $options->{isa}) { + if (exists $options->{does}) { + if (eval { $options->{isa}->can('does') }) { + ($options->{isa}->does($options->{does})) + || confess "Cannot have an isa option and a does option if the isa does not do the does on attribute $name"; + } + else { + confess "Cannot have an isa option which cannot ->does() on attribute $name"; } - } - } - elsif (exists $options->{does}) { - # allow for anon-subtypes here ... - if (blessed($options->{does}) && $options->{does}->isa('Moose::Meta::TypeConstraint')) { - $options->{type_constraint} = $options->{isa}; - } - else { - # otherwise assume it is a constraint - my $constraint = Moose::Util::TypeConstraints::find_type_constraint($options->{does}); - # if the constraing it not found .... - unless (defined $constraint) { - # assume it is a foreign class, and make - # an anon constraint for it - $constraint = Moose::Util::TypeConstraints::subtype( - 'Role', - Moose::Util::TypeConstraints::where { $_->does($options->{does}) } - ); - } - $options->{type_constraint} = $constraint; - } - } - - if (exists $options->{coerce} && $options->{coerce}) { - (exists $options->{type_constraint}) - || confess "You cannot have coercion without specifying a type constraint"; - confess "You cannot have a weak reference to a coerced value" - if $options->{weak_ref}; - } - - if (exists $options->{auto_deref} && $options->{auto_deref}) { - (exists $options->{type_constraint}) - || confess "You cannot auto-dereference without specifying a type constraint"; - ($options->{type_constraint}->is_a_type_of('ArrayRef') || + } + + # allow for anon-subtypes here ... + if (blessed($options->{isa}) && $options->{isa}->isa('Moose::Meta::TypeConstraint')) { + $options->{type_constraint} = $options->{isa}; + } + else { + $options->{type_constraint} = Moose::Util::TypeConstraints::find_or_create_isa_type_constraint($options->{isa}); + } + } + elsif (exists $options->{does}) { + # allow for anon-subtypes here ... + if (blessed($options->{does}) && $options->{does}->isa('Moose::Meta::TypeConstraint')) { + $options->{type_constraint} = $options->{does}; + } + else { + $options->{type_constraint} = Moose::Util::TypeConstraints::find_or_create_does_type_constraint($options->{does}); + } + } + + if (exists $options->{coerce} && $options->{coerce}) { + (exists $options->{type_constraint}) + || confess "You cannot have coercion without specifying a type constraint on attribute $name"; + confess "You cannot have a weak reference to a coerced value on attribute $name" + if $options->{weak_ref}; + } + + if (exists $options->{auto_deref} && $options->{auto_deref}) { + (exists $options->{type_constraint}) + || confess "You cannot auto-dereference without specifying a type constraint on attribute $name"; + ($options->{type_constraint}->is_a_type_of('ArrayRef') || $options->{type_constraint}->is_a_type_of('HashRef')) - || confess "You cannot auto-dereference anything other than a ArrayRef or HashRef"; - } - - if (exists $options->{lazy} && $options->{lazy}) { - (exists $options->{default}) - || confess "You cannot have lazy attribute without specifying a default value for it"; - } + || confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute $name"; + } + + if (exists $options->{lazy_build} && $options->{lazy_build} == 1) { + confess("You can not use lazy_build and default for the same attribute $name") + if exists $options->{default}; + $options->{lazy} = 1; + $options->{required} = 1; + $options->{builder} ||= "_build_${name}"; + if ($name =~ /^_/) { + $options->{clearer} ||= "_clear${name}"; + $options->{predicate} ||= "_has${name}"; + } + else { + $options->{clearer} ||= "clear_${name}"; + $options->{predicate} ||= "has_${name}"; + } + } + + if (exists $options->{lazy} && $options->{lazy}) { + (exists $options->{default} || defined $options->{builder} ) + || confess "You cannot have lazy attribute ($name) without specifying a default value for it"; + } + + if ( $options->{required} && !( ( !exists $options->{init_arg} || defined $options->{init_arg} ) || exists $options->{default} || defined $options->{builder} ) ) { + confess "You cannot have a required attribute ($name) without a default, builder, or an init_arg"; + } + } sub initialize_instance_slot { @@ -191,77 +241,129 @@ sub initialize_instance_slot { my $init_arg = $self->init_arg(); # try to fetch the init arg from the %params ... - my $val; - if (exists $params->{$init_arg}) { + my $val; + my $value_is_set; + if ( defined($init_arg) and exists $params->{$init_arg}) { $val = $params->{$init_arg}; + $value_is_set = 1; } else { # skip it if it's lazy return if $self->is_lazy; # and die if it's required and doesn't have a default value - confess "Attribute (" . $self->name . ") is required" - if $self->is_required && !$self->has_default; - } - - # if nothing was in the %params, we can use the - # attribute's default value (if it has one) - if (!defined $val && $self->has_default) { - $val = $self->default($instance); - } - if (defined $val) { - if ($self->has_type_constraint) { - my $type_constraint = $self->type_constraint; - if ($self->should_coerce && $type_constraint->has_coercion) { - $val = $type_constraint->coerce($val); - } - (defined($type_constraint->check($val))) - || confess "Attribute (" . - $self->name . - ") does not pass the type constraint (" . - $type_constraint->name . - ") with '$val'"; + confess "Attribute (" . $self->name . ") is required" + if $self->is_required && !$self->has_default && !$self->has_builder; + + # if nothing was in the %params, we can use the + # attribute's default value (if it has one) + if ($self->has_default) { + $val = $self->default($instance); + $value_is_set = 1; + } + elsif ($self->has_builder) { + if (my $builder = $instance->can($self->builder)){ + $val = $instance->$builder; + $value_is_set = 1; + } + else { + confess(blessed($instance)." does not support builder method '".$self->builder."' for attribute '" . $self->name . "'"); + } + } + } + + return unless $value_is_set; + + if ($self->has_type_constraint) { + my $type_constraint = $self->type_constraint; + if ($self->should_coerce && $type_constraint->has_coercion) { + $val = $type_constraint->coerce($val); } - } + $type_constraint->check($val) + || confess "Attribute (" + . $self->name + . ") does not pass the type constraint because: " + . $type_constraint->get_message($val); + } - $meta_instance->set_slot_value($instance, $self->name, $val); - $meta_instance->weaken_slot_value($instance, $self->name) + $self->set_initial_value($instance, $val); + $meta_instance->weaken_slot_value($instance, $self->name) if ref $val && $self->is_weak_ref; } ## Slot management +# FIXME: +# this duplicates too much code from +# Class::MOP::Attribute, we need to +# refactor these bits eventually. +# - SL +sub _set_initial_slot_value { + my ($self, $meta_instance, $instance, $value) = @_; + + my $slot_name = $self->name; + + return $meta_instance->set_slot_value($instance, $slot_name, $value) + unless $self->has_initializer; + + my ($type_constraint, $can_coerce); + if ($self->has_type_constraint) { + $type_constraint = $self->type_constraint; + $can_coerce = ($self->should_coerce && $type_constraint->has_coercion); + } + + my $callback = sub { + my $val = shift; + if ($type_constraint) { + $val = $type_constraint->coerce($val) + if $can_coerce; + $type_constraint->check($val) + || confess "Attribute (" + . $slot_name + . ") does not pass the type constraint because: " + . $type_constraint->get_message($val); + } + $meta_instance->set_slot_value($instance, $slot_name, $val); + }; + + my $initializer = $self->initializer; + + # most things will just want to set a value, so make it first arg + $instance->$initializer($value, $callback, $self); +} + sub set_value { my ($self, $instance, $value) = @_; - + my $attr_name = $self->name; - + if ($self->is_required) { - defined($value) + defined($value) || confess "Attribute ($attr_name) is required, so cannot be set to undef"; } - + if ($self->has_type_constraint) { - + my $type_constraint = $self->type_constraint; - + if ($self->should_coerce) { - $value = $type_constraint->coerce($value); - } - defined($type_constraint->_compiled_type_constraint->($value)) - || confess "Attribute ($attr_name) does not pass the type constraint (" - . $type_constraint->name . ") with " . (defined($value) ? ("'" . $value . "'") : "undef") - if defined($value); + $value = $type_constraint->coerce($value); + } + $type_constraint->_compiled_type_constraint->($value) + || confess "Attribute (" + . $self->name + . ") does not pass the type constraint because " + . $type_constraint->get_message($value); } - + my $meta_instance = Class::MOP::Class->initialize(blessed($instance)) ->get_meta_instance; - - $meta_instance->set_slot_value($instance, $attr_name, $value); - + + $meta_instance->set_slot_value($instance, $attr_name, $value); + if (ref $value && $self->is_weak_ref) { - $meta_instance->weaken_slot_value($instance, $attr_name); + $meta_instance->weaken_slot_value($instance, $attr_name); } - + if ($self->has_trigger) { $self->trigger->($instance, $value, $self); } @@ -269,100 +371,124 @@ sub set_value { sub get_value { my ($self, $instance) = @_; - + if ($self->is_lazy) { - unless ($self->has_value($instance)) { - if ($self->has_default) { - my $default = $self->default($instance); - $self->set_value($instance, $default); - } - else { - $self->set_value($instance, undef); - } - } + unless ($self->has_value($instance)) { + if ($self->has_default) { + my $default = $self->default($instance); + $self->set_initial_value($instance, $default); + } + if ( $self->has_builder ){ + if (my $builder = $instance->can($self->builder)){ + $self->set_initial_value($instance, $instance->$builder); + } + else { + confess(blessed($instance) + . " does not support builder method '" + . $self->builder + . "' for attribute '" + . $self->name + . "'"); + } + } + else { + $self->set_initial_value($instance, undef); + } + } } - + if ($self->should_auto_deref) { - + my $type_constraint = $self->type_constraint; if ($type_constraint->is_a_type_of('ArrayRef')) { my $rv = $self->SUPER::get_value($instance); return unless defined $rv; return wantarray ? @{ $rv } : $rv; - } + } elsif ($type_constraint->is_a_type_of('HashRef')) { my $rv = $self->SUPER::get_value($instance); return unless defined $rv; return wantarray ? %{ $rv } : $rv; - } + } else { confess "Can not auto de-reference the type constraint '" . $type_constraint->name . "'"; } - + } else { - + return $self->SUPER::get_value($instance); - } + } } -## installing accessors +## installing accessors sub accessor_metaclass { 'Moose::Meta::Method::Accessor' } sub install_accessors { my $self = shift; - $self->SUPER::install_accessors(@_); - + $self->SUPER::install_accessors(@_); + if ($self->has_handles) { - + # NOTE: # Here we canonicalize the 'handles' option - # this will sort out any details and always - # return an hash of methods which we want + # this will sort out any details and always + # return an hash of methods which we want # to delagate to, see that method for details my %handles = $self->_canonicalize_handles(); - - # find the name of the accessor for this attribute - my $accessor_name = $self->reader || $self->accessor; - (defined $accessor_name) - || confess "You cannot install delegation without a reader or accessor for the attribute"; - - # make sure we handle HASH accessors correctly - ($accessor_name) = keys %{$accessor_name} - if ref($accessor_name) eq 'HASH'; - + + # find the accessor method for this attribute + my $accessor = $self->get_read_method_ref; + # then unpack it if we need too ... + $accessor = $accessor->body if blessed $accessor; + # install the delegation ... my $associated_class = $self->associated_class; foreach my $handle (keys %handles) { my $method_to_call = $handles{$handle}; - + my $class_name = $associated_class->name; + my $name = "${class_name}::${handle}"; + (!$associated_class->has_method($handle)) || confess "You cannot overwrite a locally defined method ($handle) with a delegation"; - + # NOTE: # handles is not allowed to delegate - # any of these methods, as they will - # override the ones in your class, which + # any of these methods, as they will + # override the ones in your class, which # is almost certainly not what you want. - next if $handle =~ /^BUILD|DEMOLISH$/ || Moose::Object->can($handle); - + + # FIXME warn when $handle was explicitly specified, but not if the source is a regex or something + #cluck("Not delegating method '$handle' because it is a core method") and + next if $class_name->isa("Moose::Object") and $handle =~ /^BUILD|DEMOLISH$/ || Moose::Object->can($handle); + if ((reftype($method_to_call) || '') eq 'CODE') { - $associated_class->add_method($handle => $method_to_call); + $associated_class->add_method($handle => subname $name, $method_to_call); } else { - $associated_class->add_method($handle => sub { - # FIXME - # we should check for lack of - # a callable return value from - # the accessor here - ((shift)->$accessor_name())->$method_to_call(@_); + # NOTE: + # we used to do a goto here, but the + # goto didn't handle failure correctly + # (it just returned nothing), so I took + # that out. However, the more I thought + # about it, the less I liked it doing + # the goto, and I prefered the act of + # delegation being actually represented + # in the stack trace. + # - SL + $associated_class->add_method($handle => subname $name, sub { + my $proxy = (shift)->$accessor(); + (defined $proxy) + || confess "Cannot delegate $handle to $method_to_call because " . + "the value of " . $self->name . " is not defined"; + $proxy->$method_to_call(@_); }); } } } - + return; } @@ -371,40 +497,56 @@ sub install_accessors { sub _canonicalize_handles { my $self = shift; my $handles = $self->handles; - if (ref($handles) eq 'HASH') { - return %{$handles}; - } - elsif (ref($handles) eq 'ARRAY') { - return map { $_ => $_ } @{$handles}; - } - elsif (ref($handles) eq 'Regexp') { - ($self->has_type_constraint) - || confess "Cannot delegate methods based on a RegExpr without a type constraint (isa)"; - return map { ($_ => $_) } - grep { /$handles/ } $self->_get_delegate_method_list; - } - elsif (ref($handles) eq 'CODE') { - return $handles->($self, $self->_find_delegate_metaclass); + if (my $handle_type = ref($handles)) { + if ($handle_type eq 'HASH') { + return %{$handles}; + } + elsif ($handle_type eq 'ARRAY') { + return map { $_ => $_ } @{$handles}; + } + elsif ($handle_type eq 'Regexp') { + ($self->has_type_constraint) + || confess "Cannot delegate methods based on a RegExpr without a type constraint (isa)"; + return map { ($_ => $_) } + grep { /$handles/ } $self->_get_delegate_method_list; + } + elsif ($handle_type eq 'CODE') { + return $handles->($self, $self->_find_delegate_metaclass); + } + else { + confess "Unable to canonicalize the 'handles' option with $handles"; + } } else { - confess "Unable to canonicalize the 'handles' option with $handles"; + my $role_meta = eval { $handles->meta }; + if ($@) { + confess "Unable to canonicalize the 'handles' option with $handles because : $@"; + } + + (blessed $role_meta && $role_meta->isa('Moose::Meta::Role')) + || confess "Unable to canonicalize the 'handles' option with $handles because ->meta is not a Moose::Meta::Role"; + + return map { $_ => $_ } ( + $role_meta->get_method_list, + $role_meta->get_required_method_list + ); } } sub _find_delegate_metaclass { my $self = shift; if (my $class = $self->_isa_metadata) { - # if the class does have + # if the class does have # a meta method, use it return $class->meta if $class->can('meta'); - # otherwise we might be + # otherwise we might be # dealing with a non-Moose - # class, and need to make + # class, and need to make # our own metaclass return Moose::Meta::Class->initialize($class); } elsif (my $role = $self->_does_metadata) { - # our role will always have + # our role will always have # a meta method return $role->meta; } @@ -418,11 +560,11 @@ sub _get_delegate_method_list { my $meta = $self->_find_delegate_metaclass; if ($meta->isa('Class::MOP::Class')) { return map { $_->{name} } # NOTE: !never! delegate &meta - grep { $_->{class} ne 'Moose::Object' && $_->{name} ne 'meta' } + grep { $_->{class} ne 'Moose::Object' && $_->{name} ne 'meta' } $meta->compute_all_applicable_methods; } elsif ($meta->isa('Moose::Meta::Role')) { - return $meta->get_method_list; + return $meta->get_method_list; } else { confess "Unable to recognize the delegate metaclass '$meta'"; @@ -441,26 +583,28 @@ Moose::Meta::Attribute - The Moose attribute metaclass =head1 DESCRIPTION -This is a subclass of L with Moose specific -extensions. +This is a subclass of L with Moose specific +extensions. -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 +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. =head1 METHODS =head2 Overridden methods -These methods override methods in L and add -Moose specific features. You can safely assume though that they +These methods override methods in L and add +Moose specific features. You can safely assume though that they will behave just as L does. =over 4 =item B +=item B + =item B =item B @@ -471,19 +615,45 @@ will behave just as L does. =item B + eval { $point->meta->get_attribute('x')->set_value($point, 'fourty-two') }; + if($@) { + print "Oops: $@\n"; + } + +I + +Before setting the value, a check is made on the type constraint of +the attribute, if it has one, to see if the value passes it. If the +value fails to pass, the set operation dies with a L. + +Any coercion to convert values is done before checking the type constraint. + +To check a value against a type constraint before setting it, fetch the +attribute instance using L, +fetch the type_constraint from the attribute using L +and call L. See L +for an example. + =back =head2 Additional Moose features -Moose attributes support type-constraint checking, weak reference -creation and type coercion. +Moose attributes support type-constraint checking, weak reference +creation and type coercion. =over 4 +=item B + +=item B + +When called as a class method causes interpretation of the C and +C options. + =item B -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 +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. =item B @@ -492,8 +662,8 @@ Returns true if this meta-attribute has a type constraint. =item B -A read-only accessor for this meta-attribute's type constraint. For -more information on what you can do with this, see the documentation +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 @@ -516,7 +686,35 @@ Returns true if this meta-attribute is required to have a value. Returns true if this meta-attribute should be initialized lazily. -NOTE: lazy attributes, B have a C field set. +NOTE: lazy attributes, B have a C or C field set. + +=item B + +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. + + #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}); + + #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}); + +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. + +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 @@ -524,10 +722,10 @@ Returns true if this meta-attribute should perform type coercion. =item B -Returns true if this meta-attribute should perform automatic -auto-dereferencing. +Returns true if this meta-attribute should perform automatic +auto-dereferencing. -NOTE: This can only be done for attributes whose type constraint is +NOTE: This can only be done for attributes whose type constraint is either I or I. =item B @@ -536,16 +734,35 @@ Returns true if this meta-attribute has a trigger set. =item B -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 +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. +=item B + +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. + +=item B + +Returns true if this meta-attribute has any documentation. + +=item B + +This will return the ARRAY ref of all the traits applied to this +attribute, or if no traits have been applied, it returns C. + +=item B + +Returns true if this meta-attribute has any traits applied. + =back =head1 BUGS -All complex software has bugs lurking in it, and this module is no +All complex software has bugs lurking in it, and this module is no exception. If you find a bug please either email me, or add the bug to cpan-RT. @@ -557,11 +774,11 @@ Yuval Kogman Enothingmuch@woobling.comE =head1 COPYRIGHT AND LICENSE -Copyright 2006, 2007 by Infinity Interactive, Inc. +Copyright 2006-2008 by Infinity Interactive, Inc. L This library is free software; you can redistribute it and/or modify -it under the same terms as Perl itself. +it under the same terms as Perl itself. =cut