-#!/usr/bin/env perl
package Mouse::Meta::Attribute;
use strict;
use warnings;
-use Carp 'confess';
-use Scalar::Util 'blessed';
+use Carp ();
+use Scalar::Util qw(weaken);
+
+use Mouse::Util;
+
+use Mouse::Meta::TypeConstraint;
+use Mouse::Meta::Method::Accessor;
+
+#my %valid_attrs = map{ $_ => undef } qw(
+# name
+# reader writer accessor clearer predicate
+# builder init_arg default initializer definition_context
+#
+# is
+# isa does
+# required
+# lazy
+# lazy_build
+# coerce
+# weak_ref
+# auto_deref
+# type_constraint
+# trigger
+# handles
+# documentation
+# traits
+#);
sub new {
- my $class = shift;
- my %args = @_;
-
- my $name = $args{name};
+ my ($class, $name, %options) = @_;
- $args{init_arg} = $name
- unless exists $args{init_arg};
+ # taken from Class::MOP::Attribute::new
- $args{is} ||= '';
+ defined($name)
+ or $class->throw_error('You must provide a name for the attribute');
+ $options{name} = $name;
- bless \%args, $class;
-}
+ if(!exists $options{init_arg}){
+ $options{init_arg} = $name;
+ }
-sub name { $_[0]->{name} }
-sub class { $_[0]->{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 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} }
+ # 'required' requires eigher 'init_arg', 'builder', or 'default'
+ my $can_be_required = defined( $options{init_arg} );
-sub _create_args {
- $_[0]->{_create_args} = $_[1] if @_ > 1;
- $_[0]->{_create_args}
-}
+ if(exists $options{builder}){
+ $class->throw_error('builder must be a defined scalar value which is a method name')
+ if ref $options{builder} || !(defined $options{builder});
-sub generate_accessor {
- my $attribute = shift;
-
- my $name = $attribute->name;
- my $key = $name;
- my $default = $attribute->default;
- my $trigger = $attribute->trigger;
- my $type = $attribute->type_constraint;
- my $constraint = $attribute->find_type_constraint;
- my $builder = $attribute->builder;
-
- my $accessor = 'sub {
- my $self = shift;';
-
- if ($attribute->_is_metadata eq 'rw') {
- $accessor .= 'if (@_) {
- local $_ = $_[0];';
-
- if ($constraint) {
- $accessor .= 'do {
- my $display = defined($_) ? overload::StrVal($_) : "undef";
- Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display") unless $constraint->();
- };'
+ $can_be_required++;
+ }
+ elsif(exists $options{default}){
+ if(ref $options{default} && ref($options{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++;
+ }
- $accessor .= '$self->{$key} = $_;';
+ if( $options{required} && !$can_be_required ) {
+ $class->throw_error("You cannot have a required attribute ($name) without a default, builder, or an init_arg");
+ }
- if ($attribute->is_weak_ref) {
- $accessor .= 'Scalar::Util::weaken($self->{$key}) if ref($self->{$key});';
- }
+ # taken from Mouse::Meta::Attribute->new and _process_options
+
+ if(exists $options{is}){
+ my $is = $options{is};
- if ($trigger) {
- $accessor .= '$trigger->($self, $_, $attribute);';
+ if($is eq 'ro'){
+ $options{reader} ||= $name;
+ }
+ elsif($is eq 'rw'){
+ if(exists $options{writer}){
+ $options{reader} ||= $name;
+ }
+ else{
+ $options{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 .= '}';
+ my $tc;
+ if(exists $options{isa}){
+ $options{type_constraint} = Mouse::Util::TypeConstraints::find_or_create_isa_type_constraint($options{isa});
}
- else {
- $accessor .= 'confess "Cannot assign a value to a read-only accessor" if @_;';
+ elsif(exists $options{does}){
+ $options{type_constraint} = Mouse::Util::TypeConstraints::find_or_create_does_type_constraint($options{does});
}
+ $tc = $options{type_constraint};
- if ($attribute->is_lazy) {
- $accessor .= '$self->{$key} = ';
+ if($options{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});';
+ $options{weak_ref}
+ && $class->throw_error("You cannot have a weak reference to a coerced value on attribute ($name)");
}
- if ($attribute->should_auto_deref) {
- if ($attribute->type_constraint eq 'ArrayRef') {
- $accessor .= 'if (wantarray) {
- return @{ $self->{$key} || [] };
- }';
+ if ($options{lazy_build}) {
+ exists($options{default})
+ && $class->throw_error("You can not use lazy_build and default for the same attribute ($name)");
+
+ $options{lazy} = 1;
+ $options{builder} ||= "_build_${name}";
+ if ($name =~ /^_/) {
+ $options{clearer} ||= "_clear${name}";
+ $options{predicate} ||= "_has${name}";
}
else {
- $accessor .= 'if (wantarray) {
- return %{ $self->{$key} || {} };
- }';
+ $options{clearer} ||= "clear_${name}";
+ $options{predicate} ||= "has_${name}";
}
}
- $accessor .= 'return $self->{$key};
- }';
+ if ($options{auto_deref}) {
+ defined($tc)
+ || $class->throw_error("You cannot auto-dereference without specifying a type constraint on attribute ($name)");
- return eval $accessor;
-}
+ ( $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->name;
+ if (exists $options{trigger}) {
+ ('CODE' eq ref $options{trigger})
+ || $class->throw_error("Trigger must be a CODE ref on attribute ($name)");
+ }
- my $predicate = 'sub { exists($_[0]->{$key}) }';
+ if ($options{lazy}) {
+ (exists $options{default} || defined $options{builder})
+ || $class->throw_error("You cannot have lazy attribute ($name) without specifying a default value for it");
+ }
- return eval $predicate;
-}
+ if(my $metaclass = delete $options{metaclass}){
+ $class = Mouse::Util::resolve_metaclass_alias( Attribute => $metaclass );
+ }
-sub generate_clearer {
- my $attribute = shift;
- my $key = $attribute->name;
+ if(my $traits_ref = delete $options{traits}){
+ my @traits;
+ for (my $i = 9; $i < @{$traits_ref}; $i++) {
+ my $trait = Mouse::Util::resolve_metaclass_alias(Attribute => $traits_ref->[$i], trait => 1);
- my $predicate = 'sub { delete($_[0]->{$key}) }';
+ next if $class->does($trait);
- return eval $predicate;
-}
+ push @traits, $trait;
-sub generate_handles {
- my $attribute = shift;
- my $reader = $attribute->name;
- my %handles = $attribute->_canonicalize_handles($attribute->handles);
+ # are there options?
+ push @traits, $traits_ref->[++$i]
+ if ref($traits_ref->[$i+1]);
+ }
- my %method_map;
+ if (@traits) {
+ $class = Mouse::Meta::Class->create_anon_class(
+ superclasses => [ $class ],
+ roles => [ @traits ],
+ cache => 1,
+ )->name;
+ }
+ }
- for my $local_method (keys %handles) {
- my $remote_method = $handles{$local_method};
+# XXX: there is no fast way to check attribute validity
+# my @bad = grep{ !exists $valid_attrs{$_} } keys %options;
+# if(@bad){
+# @bad = sort @bad;
+# Carp::cluck("Found unknown argument(s) passed to '$name' attribute constructor in '$class': @bad");
+# }
- my $method = 'sub {
- my $self = shift;
- $self->$reader->$remote_method(@_)
- }';
+ return bless \%options, $class;
+}
- $method_map{$local_method} = eval $method;
- }
+# readers
+
+sub name { $_[0]->{name} }
+sub associated_class { $_[0]->{associated_class} }
+
+sub accessor { $_[0]->{accessor} }
+sub reader { $_[0]->{reader} }
+sub writer { $_[0]->{writer} }
+sub predicate { $_[0]->{predicate} }
+sub clearer { $_[0]->{clearer} }
+sub handles { $_[0]->{handles} }
+
+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 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]->{coerce} }
+
+# predicates
+
+sub has_accessor { exists $_[0]->{accessor} }
+sub has_reader { exists $_[0]->{reader} }
+sub has_writer { exists $_[0]->{writer} }
+sub has_predicate { exists $_[0]->{predicate} }
+sub has_clearer { exists $_[0]->{clearer} }
+sub has_handles { exists $_[0]->{handles} }
+
+sub has_default { exists $_[0]->{default} }
+sub has_type_constraint { exists $_[0]->{type_constraint} }
+sub has_trigger { exists $_[0]->{trigger} }
+sub has_builder { exists $_[0]->{builder} }
- return \%method_map;
+sub _create_args {
+ $_[0]->{_create_args} = $_[1] if @_ > 1;
+ $_[0]->{_create_args}
}
+sub accessor_metaclass { 'Mouse::Meta::Method::Accessor' }
+
sub create {
my ($self, $class, $name, %args) = @_;
- $args{name} = $name;
- $args{class} = $class;
-
- %args = $self->canonicalize_args($name, %args);
- $self->validate_args($name, %args);
+ my $attribute = $self->new($name, %args);
- $args{type_constraint} = delete $args{isa}
- if exists $args{isa};
-
- my $attribute = $self->new(%args);
$attribute->_create_args(\%args);
- my $meta = $class->meta;
-
- $meta->add_attribute($attribute);
+ $class->add_attribute($attribute);
+ weaken($attribute->{associated_class} = $class);
- # install an accessor
- if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') {
- my $accessor = $attribute->generate_accessor;
- no strict 'refs';
- *{ $class . '::' . $name } = $accessor;
- }
+ my $associated_methods = 0;
- for my $method (qw/predicate clearer/) {
- my $predicate = "has_$method";
- if ($attribute->$predicate) {
- my $generator = "generate_$method";
- my $coderef = $attribute->$generator;
- no strict 'refs';
- *{ $class . '::' . $attribute->$method } = $coderef;
+ my $generator_class = $self->accessor_metaclass;
+ foreach my $type(qw(accessor reader writer predicate clearer handles)){
+ if(exists $attribute->{$type}){
+ my $installer = '_install_' . $type;
+ $generator_class->$installer($attribute, $attribute->{$type}, $class);
+ $associated_methods++;
}
}
- if ($attribute->has_handles) {
- my $method_map = $attribute->generate_handles;
- for my $method_name (keys %$method_map) {
- no strict 'refs';
- *{ $class . '::' . $method_name } = $method_map->{$method_name};
- }
- }
-
- return $attribute;
-}
+ if($associated_methods == 0 && ($attribute->_is_metadata || '') ne 'bare'){
+ Carp::cluck(qq{Attribute ($name) of class }.$class->name.qq{ has no associated methods (did you mean to provide an "is" argument?)});
-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});
- }
}
- return %args;
+ return $attribute;
}
-sub validate_args {
- my $self = shift;
- my $name = shift;
- my %args = @_;
-
- confess "You can not use lazy_build and default for the same attribute ($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($args{builder});
+sub verify_against_type_constraint {
+ my ($self, $value) = @_;
+ my $tc = $self->type_constraint;
+ return 1 unless $tc;
- confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])"
- if ref($args{default})
- && ref($args{default}) ne 'CODE';
+ local $_ = $value;
+ return 1 if $tc->check($value);
- confess "You cannot auto-dereference without specifying a type constraint on attribute $name"
- if $args{auto_deref} && !exists($args{isa});
-
- confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute $name"
- if $args{auto_deref}
- && $args{isa} ne 'ArrayRef'
- && $args{isa} ne 'HashRef';
-
- confess "Trigger must be a CODE ref on attribute ($name)"
- if $args{trigger}
- && ref($args{trigger}) ne 'CODE';
-
- return 1;
+ $self->verify_type_constraint_error($self->name, $value, $tc);
}
-sub find_type_constraint {
- my $self = shift;
- my $type = $self->type_constraint;
-
- return unless $type;
-
- my $checker = Mouse::TypeRegistry->optimized_constraints->{$type};
- return $checker if $checker;
-
- return sub { blessed($_) && blessed($_) eq $type };
+sub verify_type_constraint_error {
+ my($self, $name, $value, $type) = @_;
+ $self->throw_error("Attribute ($name) does not pass the type constraint because: " . $type->get_message($value));
}
-sub verify_type_constraint {
- my $self = shift;
- local $_ = shift;
-
- my $type = $self->type_constraint
- or return 1;
- my $constraint = $self->find_type_constraint;
-
- return 1 if $constraint->($_);
-
- my $name = $self->name;
- my $display = defined($_) ? overload::StrVal($_) : 'undef';
- Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display");
+sub coerce_constraint { ## my($self, $value) = @_;
+ my $type = $_[0]->{type_constraint}
+ or return $_[1];
+ return Mouse::Util::TypeConstraints->typecast_constraints($_[0]->associated_class->name, $_[0]->type_constraint, $_[1]);
}
sub _canonicalize_handles {
return map { $_ => $_ } @$handles;
}
else {
- confess "Unable to canonicalize the 'handles' option with $handles";
+ $self->throw_error("Unable to canonicalize the 'handles' option with $handles");
}
}
my $class = shift;
my $name = shift;
- for my $super ($class->meta->linearized_isa) {
+ for my $super ($class->linearized_isa) {
my $super_attr = $super->can("meta") && $super->meta->get_attribute($name)
or next;
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 throw_error{
+ my $self = shift;
+
+ my $metaclass = (ref $self && $self->associated_class) || 'Mouse::Meta::Class';
+ $metaclass->throw_error(@_, depth => 1);
}
1;
=head2 name -> AttributeName
-=head2 class -> OwnerClass
+=head2 associated_class -> OwnerClass
=head2 is_required -> Bool
Informational methods.
-=head2 generate_accessor -> CODE
-
-Creates a new code reference for the attribute's accessor.
-
-=head2 generate_predicate -> CODE
-
-Creates a new code reference for the attribute's predicate.
-
-=head2 generate_clearer -> CODE
-
-Creates a new code reference for the attribute's clearer.
-
-=head2 generate_handles -> { MethodName => CODE }
-
-Creates a new code reference for each of the attribute's handles methods.
-
-=head2 find_type_constraint -> CODE
-
-Returns a code reference which can be used to check that a given value passes
-this attribute's type constraint;
-
-=head2 verify_type_constraint Item -> 1 | ERROR
+=head2 verify_against_type_constraint Item -> 1 | ERROR
Checks that the given value passes this attribute's type constraint. Returns 1
on success, otherwise C<confess>es.
Canonicalizes some arguments to create. In particular, C<lazy_build> is
canonicalized into C<lazy>, C<builder>, etc.
-=head2 validate_args Name, %args -> 1 | ERROR
+=head2 validate_args Name, \%args -> 1 | ERROR
Checks that the arguments to create the attribute (ie those specified by
C<has>) are valid.