X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=gitmo%2FMouse.git;a=blobdiff_plain;f=lib%2FMouse%2FMeta%2FAttribute.pm;h=c5482aa0425eef92d7a1c35d6498ceb4b7470687;hp=80ddb5149063ade4cf18150d7926f79245421fe1;hb=b06ce1f502945c13a52c503f1a651fe92c91c773;hpb=a510e63c7acd5fa667d7dce5f90b3fd07913e2d3 diff --git a/lib/Mouse/Meta/Attribute.pm b/lib/Mouse/Meta/Attribute.pm index 80ddb51..c5482aa 100644 --- a/lib/Mouse/Meta/Attribute.pm +++ b/lib/Mouse/Meta/Attribute.pm @@ -1,443 +1,287 @@ package Mouse::Meta::Attribute; -use strict; -use warnings; -require overload; +use Mouse::Util qw(:meta); # enables strict and warnings -use Carp 'confess'; -use Scalar::Util (); +use Carp (); -sub new { - my ($class, $name, %options) = @_; +use Mouse::Meta::TypeConstraint; +use Mouse::Meta::Method::Accessor; - $options{name} = $name; - $options{init_arg} = $name - unless exists $options{init_arg}; +sub _process_options{ + my($class, $name, $args) = @_; - $options{is} ||= ''; - bless \%options, $class; -} + # XXX: for backward compatibility (with method modifiers) + if($class->can('canonicalize_args') != \&canonicalize_args){ + %{$args} = $class->canonicalize_args($name, %{$args}); + } -sub name { $_[0]->{name} } -sub associated_class { $_[0]->{associated_class} } -sub _is_metadata { $_[0]->{is} } -sub is_required { $_[0]->{required} } -sub default { $_[0]->{default} } -sub is_lazy { $_[0]->{lazy} } -sub is_lazy_build { $_[0]->{lazy_build} } -sub predicate { $_[0]->{predicate} } -sub clearer { $_[0]->{clearer} } -sub handles { $_[0]->{handles} } -sub is_weak_ref { $_[0]->{weak_ref} } -sub init_arg { $_[0]->{init_arg} } -sub type_constraint { $_[0]->{type_constraint} } -sub trigger { $_[0]->{trigger} } -sub builder { $_[0]->{builder} } -sub should_auto_deref { $_[0]->{auto_deref} } -sub should_coerce { $_[0]->{should_coerce} } -sub find_type_constraint { $_[0]->{find_type_constraint} } - -sub has_default { exists $_[0]->{default} } -sub has_predicate { exists $_[0]->{predicate} } -sub has_clearer { exists $_[0]->{clearer} } -sub has_handles { exists $_[0]->{handles} } -sub has_type_constraint { exists $_[0]->{type_constraint} } -sub has_trigger { exists $_[0]->{trigger} } -sub has_builder { exists $_[0]->{builder} } - -sub _create_args { - $_[0]->{_create_args} = $_[1] if @_ > 1; - $_[0]->{_create_args} -} + # taken from Class::MOP::Attribute::new -sub inlined_name { - my $self = shift; - my $name = $self->name; - my $key = "'" . $name . "'"; - return $key; -} + defined($name) + or $class->throw_error('You must provide a name for the attribute'); -sub generate_accessor { - my $attribute = shift; - - my $name = $attribute->name; - my $default = $attribute->default; - my $constraint = $attribute->find_type_constraint; - my $builder = $attribute->builder; - my $trigger = $attribute->trigger; - my $is_weak = $attribute->is_weak_ref; - my $should_deref = $attribute->should_auto_deref; - my $should_coerce = $attribute->should_coerce; - - my $self = '$_[0]'; - my $key = $attribute->inlined_name; - - my $accessor = "sub {\n"; - if ($attribute->_is_metadata eq 'rw') { - $accessor .= 'if (@_ >= 2) {' . "\n"; - - my $value = '$_[1]'; - - if ($constraint) { - $accessor .= 'my $val = '; - if ($should_coerce) { - $accessor .= 'Mouse::Util::TypeConstraints->typecast_constraints("'.$attribute->associated_class->name.'", $attribute->{find_type_constraint}, $attribute->{type_constraint}, '.$value.');'; - } else { - $accessor .= $value.';'; - } - $accessor .= ' - unless ($constraint->($val)) { - $attribute->verify_type_constraint_error($name, $val, $attribute->type_constraint); - }' . "\n"; - $value = '$val'; - } + if(!exists $args->{init_arg}){ + $args->{init_arg} = $name; + } - # if there's nothing left to do for the attribute we can return during - # this setter - $accessor .= 'return ' if !$is_weak && !$trigger && !$should_deref; + # 'required' requires eigher 'init_arg', 'builder', or 'default' + my $can_be_required = defined( $args->{init_arg} ); - $accessor .= $self.'->{'.$key.'} = '.$value.';' . "\n"; + if(exists $args->{builder}){ + # XXX: + # Moose refuses a CODE ref builder, but Mouse doesn't for backward compatibility + # This feature will be changed in a future. (gfx) + $class->throw_error('builder must be a defined scalar value which is a method name') + #if ref $args->{builder} || !defined $args->{builder}; + if !defined $args->{builder}; - if ($is_weak) { - $accessor .= 'Scalar::Util::weaken('.$self.'->{'.$key.'}) if ref('.$self.'->{'.$key.'});' . "\n"; + $can_be_required++; + } + elsif(exists $args->{default}){ + if(ref $args->{default} && ref($args->{default}) ne 'CODE'){ + $class->throw_error("References are not allowed as default values, you must " + . "wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])"); } + $can_be_required++; + } + + if( $args->{required} && !$can_be_required ) { + $class->throw_error("You cannot have a required attribute ($name) without a default, builder, or an init_arg"); + } + + # taken from Mouse::Meta::Attribute->new and _process_args-> - if ($trigger) { - $accessor .= '$trigger->('.$self.', '.$value.');' . "\n"; + if(exists $args->{is}){ + my $is = $args->{is}; + + if($is eq 'ro'){ + $args->{reader} ||= $name; + } + elsif($is eq 'rw'){ + if(exists $args->{writer}){ + $args->{reader} ||= $name; + } + else{ + $args->{accessor} ||= $name; + } } + elsif($is eq 'bare'){ + # do nothing, but don't complain (later) about missing methods + } + else{ + $is = 'undef' if !defined $is; + $class->throw_error("I do not understand this option (is => $is) on attribute ($name)"); + } + } - $accessor .= "}\n"; + my $tc; + if(exists $args->{isa}){ + $args->{type_constraint} = Mouse::Util::TypeConstraints::find_or_create_isa_type_constraint($args->{isa}); } - else { - $accessor .= 'confess "Cannot assign a value to a read-only accessor" if scalar(@_) >= 2;' . "\n"; + elsif(exists $args->{does}){ + $args->{type_constraint} = Mouse::Util::TypeConstraints::find_or_create_does_type_constraint($args->{does}); } + $tc = $args->{type_constraint}; - if ($attribute->is_lazy) { - $accessor .= $self.'->{'.$key.'} = '; + if($args->{coerce}){ + defined($tc) + || $class->throw_error("You cannot have coercion without specifying a type constraint on attribute ($name)"); - $accessor .= $attribute->has_builder - ? $self.'->$builder' - : ref($default) eq 'CODE' - ? '$default->('.$self.')' - : '$default'; - $accessor .= ' if !exists '.$self.'->{'.$key.'};' . "\n"; + $args->{weak_ref} + && $class->throw_error("You cannot have a weak reference to a coerced value on attribute ($name)"); } - if ($should_deref) { - my $type_constraint = $attribute->type_constraint; - if (!ref($type_constraint) && $type_constraint eq 'ArrayRef') { - $accessor .= 'if (wantarray) { - return @{ '.$self.'->{'.$key.'} || [] }; - }'; + if ($args->{lazy_build}) { + exists($args->{default}) + && $class->throw_error("You can not use lazy_build and default for the same attribute ($name)"); + + $args->{lazy} = 1; + $args->{builder} ||= "_build_${name}"; + if ($name =~ /^_/) { + $args->{clearer} ||= "_clear${name}"; + $args->{predicate} ||= "_has${name}"; } else { - $accessor .= 'if (wantarray) { - return %{ '.$self.'->{'.$key.'} || {} }; - }'; + $args->{clearer} ||= "clear_${name}"; + $args->{predicate} ||= "has_${name}"; } } - $accessor .= 'return '.$self.'->{'.$key.'}; - }'; + if ($args->{auto_deref}) { + defined($tc) + || $class->throw_error("You cannot auto-dereference without specifying a type constraint on attribute ($name)"); - my $sub = eval $accessor; - confess $@ if $@; - return $sub; -} + ( $tc->is_a_type_of('ArrayRef') || $tc->is_a_type_of('HashRef') ) + || $class->throw_error("You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)"); + } -sub generate_predicate { - my $attribute = shift; - my $key = $attribute->inlined_name; + if (exists $args->{trigger}) { + ('CODE' eq ref $args->{trigger}) + || $class->throw_error("Trigger must be a CODE ref on attribute ($name)"); + } - my $predicate = 'sub { exists($_[0]->{'.$key.'}) }'; + if ($args->{lazy}) { + (exists $args->{default} || defined $args->{builder}) + || $class->throw_error("You cannot have lazy attribute ($name) without specifying a default value for it"); + } - my $sub = eval $predicate; - confess $@ if $@; - return $sub; + return; } -sub generate_clearer { - my $attribute = shift; - my $key = $attribute->inlined_name; - - my $clearer = 'sub { delete($_[0]->{'.$key.'}) }'; - - my $sub = eval $clearer; - confess $@ if $@; - return $sub; -} +sub new { + my $class = shift; + my $name = shift; -sub generate_handles { - my $attribute = shift; - my $reader = $attribute->name; - my %handles = $attribute->_canonicalize_handles($attribute->handles); + my %args = (@_ == 1) ? %{ $_[0] } : @_; - my %method_map; + $class->_process_options($name, \%args); - for my $local_method (keys %handles) { - my $remote_method = $handles{$local_method}; + $args{name} = $name; - my $method = 'sub { - my $self = shift; - $self->'.$reader.'->'.$remote_method.'(@_) - }'; + my $self = bless \%args, $class; - $method_map{$local_method} = eval $method; - confess $@ if $@; + # extra attributes + if($class ne __PACKAGE__){ + $class->meta->_initialize_object($self, \%args); } - return \%method_map; +# XXX: there is no fast way to check attribute validity +# my @bad = ...; +# if(@bad){ +# @bad = sort @bad; +# Carp::cluck("Found unknown argument(s) passed to '$name' attribute constructor in '$class': @bad"); +# } + + return $self; } -my $optimized_constraints; -sub _build_type_constraint { - my $spec = shift; - $optimized_constraints ||= Mouse::Util::TypeConstraints->optimized_constraints; - my $code; - if ($spec =~ /^([^\[]+)\[(.+)\]$/) { - # parameterized - my $constraint = $1; - my $param = $2; - my $parent; - if ($constraint eq 'Maybe') { - $parent = _build_type_constraint('Undef'); - } else { - $parent = _build_type_constraint($constraint); - } - my $child = _build_type_constraint($param); - if ($constraint eq 'ArrayRef') { - my $code_str = - "sub {\n" . - " if (\$parent->(\$_)) {\n" . - " foreach my \$e (@\$_) {\n" . - " local \$_ = \$e;\n" . - " return () unless \$child->(\$_);\n" . - " }\n" . - " return 1;\n" . - " }\n" . - " return ();\n" . - "};\n" - ; - $code = eval $code_str or Carp::confess($@); - } elsif ($constraint eq 'HashRef') { - my $code_str = - "sub {\n" . - " if (\$parent->(\$_)) {\n" . - " foreach my \$e (values %\$_) {\n" . - " local \$_ = \$e;\n" . - " return () unless \$child->(\$_);\n" . - " }\n" . - " return 1;\n" . - " }\n" . - " return ();\n" . - "};\n" - ; - $code = eval $code_str or Carp::confess($@); - } elsif ($constraint eq 'Maybe') { - my $code_str = - "sub {\n" . - " return \$child->(\$_) || \$parent->(\$_);\n" . - "};\n" - ; - $code = eval $code_str or Carp::confess($@); - } else { - Carp::confess("Support for parameterized types other than ArrayRef or HashRef is not implemented yet"); - } - $optimized_constraints->{$spec} = $code; - } else { - $code = $optimized_constraints->{ $spec }; - if (! $code) { - $code = sub { Scalar::Util::blessed($_[0]) && $_[0]->isa($spec) }; - $optimized_constraints->{$spec} = $code; - } - } - return $code; +sub has_read_method { $_[0]->has_reader || $_[0]->has_accessor } +sub has_write_method { $_[0]->has_writer || $_[0]->has_accessor } + +sub _create_args { # DEPRECATED + $_[0]->{_create_args} = $_[1] if @_ > 1; + $_[0]->{_create_args} } -sub create { - my ($self, $class, $name, %args) = @_; +sub interpolate_class{ + my($class, $args) = @_; - $args{name} = $name; - $args{associated_class} = $class; - - %args = $self->canonicalize_args($name, %args); - $self->validate_args($name, \%args); - - $args{should_coerce} = delete $args{coerce} - if exists $args{coerce}; - - if (exists $args{isa}) { - confess "Got isa => $args{isa}, but Mouse does not yet support parameterized types for containers other than ArrayRef and HashRef (rt.cpan.org #39795)" - if $args{isa} =~ /^([^\[]+)\[.+\]$/ && - $1 ne 'ArrayRef' && - $1 ne 'HashRef' && - $1 ne 'Maybe' - ; - - my $type_constraint = delete $args{isa}; - $type_constraint =~ s/\s//g; - my @type_constraints = split /\|/, $type_constraint; - - my $code; - if (@type_constraints == 1) { - $code = _build_type_constraint($type_constraints[0]); - $args{type_constraint} = $type_constraints[0]; - } else { - my @code_list = map { - _build_type_constraint($_) - } @type_constraints; - $code = sub { - local $_ = $_[0]; - for my $code (@code_list) { - return 1 if $code->($_); - } - return 0; - }; - $args{type_constraint} = \@type_constraints; - } - $args{find_type_constraint} = $code; + if(my $metaclass = delete $args->{metaclass}){ + $class = Mouse::Util::resolve_metaclass_alias( Attribute => $metaclass ); } - my $attribute = $self->new($name, %args); + my @traits; + if(my $traits_ref = delete $args->{traits}){ - $attribute->_create_args(\%args); + for (my $i = 0; $i < @{$traits_ref}; $i++) { + my $trait = Mouse::Util::resolve_metaclass_alias(Attribute => $traits_ref->[$i], trait => 1); - $class->add_attribute($attribute); + next if $class->does($trait); - # install an accessor - if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') { - my $accessor = $attribute->generate_accessor; - $class->add_method($name => $accessor); - } + push @traits, $trait; - for my $method (qw/predicate clearer/) { - my $predicate = "has_$method"; - if ($attribute->$predicate) { - my $generator = "generate_$method"; - my $coderef = $attribute->$generator; - $class->add_method($attribute->$method => $coderef); + # are there options? + push @traits, $traits_ref->[++$i] + if ref($traits_ref->[$i+1]); } - } - if ($attribute->has_handles) { - my $method_map = $attribute->generate_handles; - for my $method_name (keys %$method_map) { - $class->add_method($method_name => $method_map->{$method_name}); + if (@traits) { + $class = Mouse::Meta::Class->create_anon_class( + superclasses => [ $class ], + roles => \@traits, + cache => 1, + )->name; } } - return $attribute; + return( $class, @traits ); } -sub canonicalize_args { - my $self = shift; - my $name = shift; - my %args = @_; - - if ($args{lazy_build}) { - $args{lazy} = 1; - $args{required} = 1; - $args{builder} = "_build_${name}" - if !exists($args{builder}); - if ($name =~ /^_/) { - $args{clearer} = "_clear${name}" if !exists($args{clearer}); - $args{predicate} = "_has${name}" if !exists($args{predicate}); - } - else { - $args{clearer} = "clear_${name}" if !exists($args{clearer}); - $args{predicate} = "has_${name}" if !exists($args{predicate}); - } - } +sub canonicalize_args{ # DEPRECATED + my ($self, $name, %args) = @_; + + Carp::cluck("$self->canonicalize_args has been deprecated." + . "Use \$self->_process_options instead.") + if _MOUSE_VERBOSE; return %args; } -sub validate_args { - my $self = shift; - my $name = shift; - my $args = shift; - - confess "You can not use lazy_build and default for the same attribute ($name)" - if $args->{lazy_build} && exists $args->{default}; - - confess "You cannot have lazy attribute ($name) without specifying a default value for it" - if $args->{lazy} - && !exists($args->{default}) - && !exists($args->{builder}); +sub create { # DEPRECATED + my ($self, $class, $name, %args) = @_; - confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])" - if ref($args->{default}) - && ref($args->{default}) ne 'CODE'; + Carp::cluck("$self->create has been deprecated." + . "Use \$meta->add_attribute and \$attr->install_accessors instead.") + if _MOUSE_VERBOSE; - confess "You cannot auto-dereference without specifying a type constraint on attribute ($name)" - if $args->{auto_deref} && !exists($args->{isa}); + # noop + return $self; +} - confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)" - if $args->{auto_deref} - && $args->{isa} ne 'ArrayRef' - && $args->{isa} ne 'HashRef'; +sub _coerce_and_verify { + my($self, $value, $instance) = @_; - if ($args->{trigger}) { - if (ref($args->{trigger}) eq 'HASH') { - Carp::carp "HASH-based form of trigger has been removed. Only the coderef form of triggers are now supported."; - } + my $type_constraint = $self->{type_constraint}; + return $value if !defined $type_constraint; - confess "Trigger must be a CODE ref on attribute ($name)" - if ref($args->{trigger}) ne 'CODE'; + if ($self->should_coerce && $type_constraint->has_coercion) { + $value = $type_constraint->coerce($value); } - return 1; + $self->verify_against_type_constraint($value); + + return $value; } sub verify_against_type_constraint { - return 1 unless $_[0]->{type_constraint}; + my ($self, $value) = @_; - local $_ = $_[1]; - return 1 if $_[0]->{find_type_constraint}->($_); + my $type_constraint = $self->{type_constraint}; + return 1 if !$type_constraint; + return 1 if $type_constraint->check($value); - my $self = shift; - $self->verify_type_constraint_error($self->name, $_, $self->type_constraint); + $self->verify_type_constraint_error($self->name, $value, $type_constraint); } sub verify_type_constraint_error { my($self, $name, $value, $type) = @_; - $type = ref($type) eq 'ARRAY' ? join '|', @{ $type } : $type; - my $display = defined($value) ? overload::StrVal($value) : 'undef'; - Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display"); + $self->throw_error("Attribute ($name) does not pass the type constraint because: " + . $type->get_message($value)); } -sub coerce_constraint { ## my($self, $value) = @_; +sub coerce_constraint { # DEPRECATED my $type = $_[0]->{type_constraint} or return $_[1]; - return Mouse::Util::TypeConstraints->typecast_constraints($_[0]->associated_class->name, $_[0]->find_type_constraint, $type, $_[1]); + + Carp::cluck("coerce_constraint() has been deprecated, which was an internal utility anyway"); + + return Mouse::Util::TypeConstraints->typecast_constraints($_[0]->associated_class->name, $type, $_[1]); } -sub _canonicalize_handles { - my $self = shift; - my $handles = shift; +sub clone_and_inherit_options{ + my($self, %args) = @_; - if (ref($handles) eq 'HASH') { - return %$handles; - } - elsif (ref($handles) eq 'ARRAY') { - return map { $_ => $_ } @$handles; - } - else { - confess "Unable to canonicalize the 'handles' option with $handles"; - } + my($attribute_class, @traits) = ref($self)->interpolate_class(\%args); + + $args{traits} = \@traits if @traits; + return $attribute_class->new($self->name, %{$self}, %args); } -sub clone_parent { +sub clone_parent { # DEPRECATED my $self = shift; my $class = shift; my $name = shift; my %args = ($self->get_parent_args($class, $name), @_); - $self->create($class, $name, %args); + Carp::cluck("$self->clone_parent has been deprecated." + . "Use \$meta->add_attribute and \$attr->install_accessors instead.") + if _MOUSE_VERBOSE; + + $self->clone_and_inherited_args($class, $name, %args); } -sub get_parent_args { +sub get_parent_args { # DEPRECATED my $self = shift; my $class = shift; my $name = shift; @@ -448,7 +292,123 @@ sub get_parent_args { return %{ $super_attr->_create_args }; } - confess "Could not find an attribute by the name of '$name' to inherit from"; + $self->throw_error("Could not find an attribute by the name of '$name' to inherit from"); +} + + +sub get_read_method { + $_[0]->reader || $_[0]->accessor +} +sub get_write_method { + $_[0]->writer || $_[0]->accessor +} + +sub get_read_method_ref{ + my($self) = @_; + + $self->{_read_method_ref} ||= do{ + my $metaclass = $self->associated_class + or $self->throw_error('No asocciated class for ' . $self->name); + + my $reader = $self->{reader} || $self->{accessor}; + if($reader){ + $metaclass->name->can($reader); + } + else{ + $self->accessor_metaclass->_generate_reader($self, $metaclass); + } + }; +} + +sub get_write_method_ref{ + my($self) = @_; + + $self->{_write_method_ref} ||= do{ + my $metaclass = $self->associated_class + or $self->throw_error('No asocciated class for ' . $self->name); + + my $reader = $self->{writer} || $self->{accessor}; + if($reader){ + $metaclass->name->can($reader); + } + else{ + $self->accessor_metaclass->_generate_writer($self, $metaclass); + } + }; +} + +sub _canonicalize_handles { + my($self, $handles) = @_; + + if (ref($handles) eq 'HASH') { + return %$handles; + } + elsif (ref($handles) eq 'ARRAY') { + return map { $_ => $_ } @$handles; + } + elsif (ref($handles) eq 'Regexp') { + my $class_or_role = ($self->{isa} || $self->{does}) + || $self->throw_error("Cannot delegate methods based on a Regexp without a type constraint (isa)"); + + my $meta = Mouse::Meta::Class->initialize("$class_or_role"); # "" for stringify + return map { $_ => $_ } + grep { $_ ne 'meta' && !Mouse::Object->can($_) && $_ =~ $handles } + $meta->isa('Mouse::Meta::Class') ? $meta->get_all_method_names : $meta->get_method_list; + } + else { + $self->throw_error("Unable to canonicalize the 'handles' option with $handles"); + } +} + +sub associate_method{ + my ($attribute, $method) = @_; + $attribute->{associated_methods}++; + return; +} + +sub install_accessors{ + my($attribute) = @_; + + my $metaclass = $attribute->associated_class; + my $accessor_class = $attribute->accessor_metaclass; + + foreach my $type(qw(accessor reader writer predicate clearer)){ + if(exists $attribute->{$type}){ + my $generator = '_generate_' . $type; + my $code = $accessor_class->$generator($attribute, $metaclass); + $metaclass->add_method($attribute->{$type} => $code); + $attribute->associate_method($code); + } + } + + # install delegation + if(exists $attribute->{handles}){ + my %handles = $attribute->_canonicalize_handles($attribute->{handles}); + my $reader = $attribute->get_read_method_ref; + + while(my($handle_name, $method_to_call) = each %handles){ + my $code = $accessor_class->_generate_delegation($attribute, $metaclass, + $reader, $handle_name, $method_to_call); + + $metaclass->add_method($handle_name => $code); + $attribute->associate_method($code); + } + } + + + if($attribute->can('create') != \&create){ + # backword compatibility + $attribute->create($metaclass, $attribute->name, %{$attribute}); + } + + return; +} + +sub throw_error{ + my $self = shift; + + my $metaclass = (ref $self && $self->associated_class) || 'Mouse::Meta::Class'; + $metaclass->throw_error(@_, depth => 1); } 1; @@ -457,110 +417,149 @@ __END__ =head1 NAME -Mouse::Meta::Attribute - attribute metaclass +Mouse::Meta::Attribute - The Mouse attribute metaclass + +=head1 VERSION + +This document describes Mouse version 0.40_01 =head1 METHODS -=head2 new %args -> Mouse::Meta::Attribute +=head2 C<< new(%options) -> Mouse::Meta::Attribute >> Instantiates a new Mouse::Meta::Attribute. Does nothing else. -=head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute +It adds the following options to the constructor: + +=over 4 -Creates a new attribute in OwnerClass. Accessors and helper methods are -installed. Some error checking is done. +=item C<< is => 'ro', 'rw', 'bare' >> -=head2 name -> AttributeName +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. -=head2 associated_class -> OwnerClass +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. -=head2 is_required -> Bool +Use 'bare' when you are deliberately not installing any methods +(accessor, reader, etc.) associated with this attribute; otherwise, +Moose will issue a deprecation warning when this attribute is added to a +metaclass. -=head2 default -> Item +=item C<< isa => Type >> -=head2 has_default -> Bool +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. -=head2 is_lazy -> Bool +This option can also accept a L object. -=head2 predicate -> MethodName | Undef +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. -=head2 has_predicate -> Bool +=item C<< does => Role >> -=head2 clearer -> MethodName | Undef +This is short-hand for saying that the attribute's type must be an +object which does the named role. -=head2 has_clearer -> Bool +B -=head2 handles -> { LocalName => RemoteName } +=item C<< coerce => Bool >> -=head2 has_handles -> 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. -=head2 is_weak_ref -> Bool +You can make both this and the C option true. -=head2 init_arg -> Str +=item C<< trigger => CodeRef >> -=head2 type_constraint -> Str +This option accepts a subroutine reference, which will be called after +the attribute is set. -=head2 has_type_constraint -> Bool +=item C<< required => Bool >> -=head2 trigger => CODE | Undef +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 satisfy its required-ness. -=head2 has_trigger -> Bool +A required attribute must have a C, C or a +non-C C -=head2 builder => MethodName | Undef +=item C<< lazy => Bool >> -=head2 has_builder -> 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. -=head2 is_lazy_build => Bool +=item C<< weak_ref => Bool >> -=head2 should_auto_deref -> Bool +If this is true, the attribute's value will be stored as a weak +reference. -Informational methods. +=item C<< auto_deref => Bool >> -=head2 generate_accessor -> CODE +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. -Creates a new code reference for the attribute's accessor. +=item C<< lazy_build => Bool >> -=head2 generate_predicate -> CODE +Setting this to true makes the attribute lazy and provides a number of +default methods. -Creates a new code reference for the attribute's predicate. + has 'size' => ( + is => 'ro', + lazy_build => 1, + ); -=head2 generate_clearer -> CODE +is equivalent to this: -Creates a new code reference for the attribute's clearer. + has 'size' => ( + is => 'ro', + lazy => 1, + builder => '_build_size', + clearer => 'clear_size', + predicate => 'has_size', + ); -=head2 generate_handles -> { MethodName => CODE } +=back -Creates a new code reference for each of the attribute's handles methods. +=head2 C<< associate_method(Method) >> -=head2 find_type_constraint -> CODE +Associates a method with the attribute. Typically, this is called internally +when an attribute generates its accessors. -Returns a code reference which can be used to check that a given value passes -this attribute's type constraint; +Currently the argument I is ignored in Mouse. -=head2 verify_against_type_constraint Item -> 1 | ERROR +=head2 C<< verify_against_type_constraint(Item) -> TRUE | ERROR >> -Checks that the given value passes this attribute's type constraint. Returns 1 +Checks that the given value passes this attribute's type constraint. Returns C on success, otherwise Ces. -=head2 canonicalize_args Name, %args -> %args +=head2 C<< clone_and_inherit_options(options) -> Mouse::Meta::Attribute >> -Canonicalizes some arguments to create. In particular, C is -canonicalized into C, C, etc. +Creates a new attribute in the owner class, inheriting options from parent classes. +Accessors and helper methods are installed. Some error checking is done. -=head2 validate_args Name, \%args -> 1 | ERROR +=head2 C<< get_read_method_ref >> -Checks that the arguments to create the attribute (ie those specified by -C) are valid. +=head2 C<< get_write_method_ref >> -=head2 clone_parent OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute +Returns the subroutine reference of a method suitable for reading or +writing the attribute's value in the associated class. These methods +always return a subroutine reference, regardless of whether or not the +attribute is read- or write-only. -Creates a new attribute in OwnerClass, inheriting options from parent classes. -Accessors and helper methods are installed. Some error checking is done. +=head1 SEE ALSO -=head2 get_parent_args OwnerClass, AttributeName -> Hash +L -Returns the options that the parent class of C used for attribute -C. +L =cut