X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FMoose%2FMeta%2FAttribute.pm;h=28c0b8b02039b897b76e44521731da347f490bf4;hb=ccf49e80884ce57511f742a85791d368a372d893;hp=5feaf85b2a61e6f7d386dddfde7fe82bf3d9ef42;hpb=093b12c2fa259436d60be95e4d540085c529cced;p=gitmo%2FMoose.git diff --git a/lib/Moose/Meta/Attribute.pm b/lib/Moose/Meta/Attribute.pm index 5feaf85..28c0b8b 100644 --- a/lib/Moose/Meta/Attribute.pm +++ b/lib/Moose/Meta/Attribute.pm @@ -6,9 +6,13 @@ use warnings; use Scalar::Util 'blessed', 'weaken', 'reftype'; use Carp 'confess'; +use Sub::Name 'subname'; +use overload (); -our $VERSION = '0.06'; +our $VERSION = '0.18'; +our $AUTHORITY = 'cpan:STEVAN'; +use Moose::Meta::Method::Accessor; use Moose::Util::TypeConstraints (); use base 'Class::MOP::Attribute'; @@ -22,6 +26,7 @@ __PACKAGE__->meta->add_attribute('is' => (reader => '_is_metadata')); # these are actual options for the attrs __PACKAGE__->meta->add_attribute('required' => (reader => 'is_required' )); __PACKAGE__->meta->add_attribute('lazy' => (reader => 'is_lazy' )); +__PACKAGE__->meta->add_attribute('lazy_build' => (reader => 'is_lazy_build' )); __PACKAGE__->meta->add_attribute('coerce' => (reader => 'should_coerce' )); __PACKAGE__->meta->add_attribute('weak_ref' => (reader => 'is_weak_ref' )); __PACKAGE__->meta->add_attribute('auto_deref' => (reader => 'should_auto_deref')); @@ -37,147 +42,163 @@ __PACKAGE__->meta->add_attribute('handles' => ( reader => 'handles', predicate => 'has_handles', )); +__PACKAGE__->meta->add_attribute('documentation' => ( + reader => 'documentation', + predicate => 'has_documentation', +)); sub new { - my ($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 clone_and_inherit_options { my ($self, %options) = @_; - # you can change default, required and coerce + # you can change default, required, coerce, documentation and lazy my %actual_options; - foreach my $legal_option (qw(default coerce required)) { + foreach my $legal_option (qw(default coerce required documentation lazy)) { 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 + + # handles can only be added, not changed + if ($options{handles}) { + confess "You can only add the 'handles' option, you cannot change it" + if $self->has_handles; + $actual_options{handles} = $options{handles}; + delete $options{handles}; + } + + # isa can be changed, but only if the + # new type is a subtype if ($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 '" . $options{isa} . "'"; - } - ($type_constraint->is_subtype_of($self->type_constraint->name)) - || confess "New type constraint setting must be a subtype of inherited one" - if $self->has_type_constraint; - $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_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; delete $options{isa}; } - (scalar keys %options == 0) + (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 $options->{trigger}) + || confess "Cannot have a trigger on a read-only attribute"; + } + elsif ($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"; } - } - } - 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 $options->{type_constraint}) - || confess "You cannot have coercion without specifying a type constraint"; - (!$options->{type_constraint}->isa('Moose::Meta::TypeConstraint::Union')) - || confess "You cannot have coercion with a type constraint union"; + 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 { + $options->{type_constraint} = Moose::Util::TypeConstraints::find_or_create_type_constraint( + $options->{isa} => { + parent => Moose::Util::TypeConstraints::find_type_constraint('Object'), + constraint => sub { $_[0]->isa($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_type_constraint( + $options->{does} => { + parent => Moose::Util::TypeConstraints::find_type_constraint('Role'), + constraint => sub { + Moose::Util::does_role($_[0], $options->{does}) + } + } + ); + } + } + + 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}->name =~ /^ArrayRef|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"; - } + 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') || + $options->{type_constraint}->is_a_type_of('HashRef')) + || confess "You cannot auto-dereference anything other than a ArrayRef or HashRef"; + } + + if (exists $options->{lazy_build} && $options->{lazy_build} == 1) { + confess("You can not use lazy_build and default for the same attribute") + 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} || exists $options->{builder} ) + || confess "You cannot have lazy attribute without specifying a default value for it"; + } + } sub initialize_instance_slot { @@ -185,222 +206,214 @@ sub initialize_instance_slot { my $init_arg = $self->init_arg(); # try to fetch the init arg from the %params ... - my $val; + my $val; + my $value_is_set; if (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; + 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 . "'"); + } + } } - # 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 = $type_constraint->coercion->coerce($val); - } - (defined($type_constraint->check($val))) - || confess "Attribute (" . - $self->name . - ") does not pass the type constraint (" . - $type_constraint->name . - ") with '$val'"; + 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); } - } + (defined($type_constraint->check($val))) + || confess "Attribute (" . + $self->name . + ") does not pass the type constraint (" . + $type_constraint->name . + ") with '" . + (defined $val + ? overload::StrVal($val) + : 'undef') . + "'"; + } $meta_instance->set_slot_value($instance, $self->name, $val); - $meta_instance->weaken_slot_value($instance, $self->name) + $meta_instance->weaken_slot_value($instance, $self->name) if ref $val && $self->is_weak_ref; } -## Accessor inline subroutines - -sub _inline_check_constraint { - my ($self, $value) = @_; - return '' unless $self->has_type_constraint; - - # FIXME - remove 'unless defined($value) - constraint Undef - return sprintf <<'EOF', $value, $value, $value, $value -defined($attr->type_constraint->check(%s)) - || confess "Attribute (" . $attr->name . ") does not pass the type constraint (" - . $attr->type_constraint->name . ") with " . (defined(%s) ? "'%s'" : "undef") - if defined(%s); -EOF -} +## Slot management -sub _inline_check_coercion { - my $self = shift; - return '' unless $self->should_coerce; - return 'my $val = $attr->type_constraint->coercion->coerce($_[1]);' -} +sub set_value { + my ($self, $instance, $value) = @_; -sub _inline_check_required { - my $self = shift; - return '' unless $self->is_required; - return 'defined($_[1]) || confess "Attribute ($attr_name) is required, so cannot be set to undef";' -} - -sub _inline_check_lazy { - my $self = shift; - return '' unless $self->is_lazy; - return '$_[0]->{$attr_name} = ($attr->has_default ? $attr->default($_[0]) : undef)' - . 'unless exists $_[0]->{$attr_name};'; -} + my $attr_name = $self->name; + if ($self->is_required) { + defined($value) + || confess "Attribute ($attr_name) is required, so cannot be set to undef"; + } -sub _inline_store { - my ($self, $instance, $value) = @_; + if ($self->has_type_constraint) { - my $mi = $self->associated_class->get_meta_instance; - my $slot_name = sprintf "'%s'", $self->slots; + my $type_constraint = $self->type_constraint; - my $code = $mi->inline_set_slot_value($instance, $slot_name, $value) . ";"; - $code .= $mi->inline_weaken_slot_value($instance, $slot_name, $value) . ";" - if $self->is_weak_ref; - return $code; -} + if ($self->should_coerce) { + $value = $type_constraint->coerce($value); + } + $type_constraint->_compiled_type_constraint->($value) + || confess "Attribute ($attr_name) does not pass the type constraint (" + . $type_constraint->name + . ") with " + . (defined($value) + ? ("'" . overload::StrVal($value) . "'") + : "undef") + if defined($value); + } -sub _inline_trigger { - my ($self, $instance, $value) = @_; - return '' unless $self->has_trigger; - return sprintf('$attr->trigger->(%s, %s, $attr);', $instance, $value); -} + my $meta_instance = Class::MOP::Class->initialize(blessed($instance)) + ->get_meta_instance; -sub _inline_get { - my ($self, $instance) = @_; + $meta_instance->set_slot_value($instance, $attr_name, $value); - my $mi = $self->associated_class->get_meta_instance; - my $slot_name = sprintf "'%s'", $self->slots; + if (ref $value && $self->is_weak_ref) { + $meta_instance->weaken_slot_value($instance, $attr_name); + } - return $mi->inline_get_slot_value($instance, $slot_name); + if ($self->has_trigger) { + $self->trigger->($instance, $value, $self); + } } -sub _inline_auto_deref { - my ( $self, $ref_value ) = @_; +sub get_value { + my ($self, $instance) = @_; - return $ref_value unless $self->should_auto_deref; + if ($self->is_lazy) { + unless ($self->has_value($instance)) { + if ($self->has_default) { + my $default = $self->default($instance); + $self->set_value($instance, $default); + } + if ( $self->has_builder ){ + if (my $builder = $instance->can($self->builder)){ + $self->set_value($instance, $instance->$builder); + } + else { + confess(blessed($instance) + . " does not support builder method '" + . $self->builder + . "' for attribute '" + . $self->name + . "'"); + } + } + else { + $self->set_value($instance, undef); + } + } + } - my $type = $self->type_constraint->name; + if ($self->should_auto_deref) { - my $sigil; - if ($type eq "ArrayRef") { - $sigil = '@'; - } - elsif ($type eq 'HashRef') { - $sigil = '%'; - } - else { - confess "Can not auto de-reference the type constraint '$type'"; - } + my $type_constraint = $self->type_constraint; - "(wantarray() ? $sigil\{ ( $ref_value ) || return } : ( $ref_value ) )"; -} + if ($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 '" . $type_constraint->name . "'"; + } -sub generate_accessor_method { - my ($attr, $attr_name) = @_; - my $value_name = $attr->should_coerce ? '$val' : '$_[1]'; - my $mi = $attr->associated_class->get_meta_instance; - my $slot_name = sprintf "'%s'", $attr->slots; - my $inv = '$_[0]'; - my $code = 'sub { ' - . 'if (scalar(@_) == 2) {' - . $attr->_inline_check_required - . $attr->_inline_check_coercion - . $attr->_inline_check_constraint($value_name) - . $attr->_inline_store($inv, $value_name) - . $attr->_inline_trigger($inv, $value_name) - . ' }' - . $attr->_inline_check_lazy - . 'return ' . $attr->_inline_auto_deref($attr->_inline_get($inv)) - . ' }'; - my $sub = eval $code; - confess "Could not create accessor for '$attr_name' because $@ \n code: $code" if $@; - return $sub; -} + } + else { -sub generate_writer_method { - my ($attr, $attr_name) = @_; - my $value_name = $attr->should_coerce ? '$val' : '$_[1]'; - my $inv = '$_[0]'; - my $code = 'sub { ' - . $attr->_inline_check_required - . $attr->_inline_check_coercion - . $attr->_inline_check_constraint($value_name) - . $attr->_inline_store($inv, $value_name) - . $attr->_inline_trigger($inv, $value_name) - . ' }'; - my $sub = eval $code; - confess "Could not create writer for '$attr_name' because $@ \n code: $code" if $@; - return $sub; + return $self->SUPER::get_value($instance); + } } -sub generate_reader_method { - my $attr = shift; - my $attr_name = $attr->slots; - my $code = 'sub {' - . 'confess "Cannot assign a value to a read-only accessor" if @_ > 1;' - . $attr->_inline_check_lazy - . 'return ' . $attr->_inline_auto_deref( '$_[0]->{$attr_name}' ) . ';' - . '}'; - my $sub = eval $code; - confess "Could not create reader for '$attr_name' because $@ \n code: $code" if $@; - return $sub; -} +## 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 + # is almost certainly not what you want. + + # 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(@_); + $associated_class->add_method($handle => subname $name, sub { + my $proxy = (shift)->$accessor(); + @_ = ($proxy, @_); + (defined $proxy) + || confess "Cannot delegate $handle to $method_to_call because " . + "the value of " . $self->name . " is not defined"; + goto &{ $proxy->can($method_to_call) || return }; }); } } } - + return; } @@ -409,40 +422,56 @@ 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; } @@ -456,11 +485,11 @@ 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'"; @@ -479,20 +508,20 @@ 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 @@ -501,27 +530,46 @@ will behave just as L does. =item B -=item B +=item B -=item B +=item B -=item B +=item B -=item B +=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 -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 @@ -530,8 +578,8 @@ 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 @@ -554,7 +602,35 @@ 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 @@ -562,10 +638,10 @@ 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 @@ -574,16 +650,26 @@ 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. + =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. @@ -595,11 +681,11 @@ Yuval Kogman Enothingmuch@woobling.comE =head1 COPYRIGHT AND LICENSE -Copyright 2006 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