#!/usr/bin/env perl
-package Mouse::Attribute;
+package Mouse::Meta::Attribute;
use strict;
use warnings;
my $class = shift;
my %args = @_;
- $args{init_arg} = $args{name}
+ my $name = $args{name};
+
+ $args{init_arg} = $name
unless exists $args{init_arg};
+
$args{is} ||= '';
bless \%args, $class;
}
-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 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 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 has_default { exists $_[0]->{default} }
sub has_predicate { exists $_[0]->{predicate} }
sub has_trigger { exists $_[0]->{trigger} }
sub has_builder { exists $_[0]->{builder} }
+sub _create_args {
+ $_[0]->{_create_args} = $_[1] if @_ > 1;
+ $_[0]->{_create_args}
+}
+
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 $trigger = $attribute->trigger;
+ my $before = $trigger->{before};
+ my $after = $trigger->{after};
+ my $around = $trigger->{around};
+
my $accessor = 'sub {
my $self = shift;';
$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 $constraint->();
- };'
+ if ($before) {
+ $accessor .= '$before->($self, $_, $attribute);';
+ }
+
+ if ($around) {
+ $accessor .= '$around->(sub {
+ my $self = shift;
+ $_ = $_[0];
+ ';
}
- $accessor .= '$self->{$key} = $_;';
+ if ($constraint) {
+ $accessor .= 'unless ($constraint->()) {
+ my $display = defined($_) ? overload::StrVal($_) : "undef";
+ Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display");
+ }'
+ }
- if ($attribute->is_weak_ref) {
- $accessor .= 'Scalar::Util::weaken($self->{$key}) if ref($self->{$key});';
+ $accessor .= '$self->{$key} = $_;';
+
+ if ($attribute->is_weak_ref) {
+ $accessor .= 'Scalar::Util::weaken($self->{$key}) if ref($self->{$key});';
+ }
+
+ if ($around) {
+ $accessor .= '}, $self, $_, $attribute);';
}
- if ($trigger) {
- $accessor .= '$trigger->($self, $_, $attribute);';
+ if ($after) {
+ $accessor .= '$after->($self, $_, $attribute);';
}
$accessor .= '}';
$accessor .= ' if !exists($self->{$key});';
}
- $accessor .= 'return $self->{$key}
+ if ($attribute->should_auto_deref) {
+ if ($attribute->type_constraint eq 'ArrayRef') {
+ $accessor .= 'if (wantarray) {
+ return @{ $self->{$key} || [] };
+ }';
+ }
+ else {
+ $accessor .= 'if (wantarray) {
+ return %{ $self->{$key} || {} };
+ }';
+ }
+ }
+
+ $accessor .= 'return $self->{$key};
}';
return eval $accessor;
sub create {
my ($self, $class, $name, %args) = @_;
- confess "You cannot have lazy attribute ($name) without specifying a default value for it"
- if $args{lazy} && !exists($args{default}) && !exists($args{builder});
+ $args{name} = $name;
+ $args{associated_class} = $class;
- confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])"
- if ref($args{default})
- && ref($args{default}) ne 'CODE';
+ %args = $self->canonicalize_args($name, %args);
+ $self->validate_args($name, \%args);
$args{type_constraint} = delete $args{isa}
if exists $args{isa};
- my $attribute = $self->new(%args, name => $name, class => $class);
+ my $attribute = $self->new(%args);
+ $attribute->_create_args(\%args);
+
my $meta = $class->meta;
$meta->add_attribute($attribute);
return $attribute;
}
+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;
+}
+
+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($args->{builder});
+
+ confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])"
+ if ref($args->{default})
+ && ref($args->{default}) ne 'CODE';
+
+ 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'
+ && $args->{isa} ne 'HashRef';
+
+ if ($args->{trigger}) {
+ if (ref($args->{trigger}) eq 'CODE') {
+ $args->{trigger} = {
+ after => $args->{trigger},
+ };
+ }
+
+ confess "Trigger must be a CODE or HASH ref on attribute ($name)"
+ if ref($args->{trigger}) ne 'HASH';
+ }
+
+ return 1;
+}
+
sub find_type_constraint {
my $self = shift;
my $type = $self->type_constraint;
}
}
+sub clone_parent {
+ my $self = shift;
+ my $class = shift;
+ my $name = shift;
+ my %args = ($self->get_parent_args($class, $name), @_);
+
+ $self->create($class, $name, %args);
+}
+
+sub get_parent_args {
+ my $self = shift;
+ my $class = shift;
+ my $name = shift;
+
+ for my $super ($class->meta->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";
+}
+
1;
__END__
=head1 NAME
-Mouse::Attribute - attribute metaclass
+Mouse::Meta::Attribute - attribute metaclass
=head1 METHODS
-=head2 new %args -> Mouse::Attribute
+=head2 new %args -> Mouse::Meta::Attribute
-Instantiates a new Mouse::Attribute. Does nothing else.
+Instantiates a new Mouse::Meta::Attribute. Does nothing else.
-=head2 create OwnerClass, AttributeName, %args -> Mouse::Attribute
+=head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
Creates a new attribute in OwnerClass. Accessors and helper methods are
installed. Some error checking is done.
=head2 name -> AttributeName
-=head2 class -> OwnerClass
+=head2 associated_class -> OwnerClass
=head2 is_required -> Bool
=head2 has_builder -> Bool
+=head2 is_lazy_build => Bool
+
+=head2 should_auto_deref -> Bool
+
Informational methods.
=head2 generate_accessor -> CODE
Checks that the given value passes this attribute's type constraint. Returns 1
on success, otherwise C<confess>es.
+=head2 canonicalize_args Name, %args -> %args
+
+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
+
+Checks that the arguments to create the attribute (ie those specified by
+C<has>) are valid.
+
+=head2 clone_parent OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
+
+Creates a new attribute in OwnerClass, inheriting options from parent classes.
+Accessors and helper methods are installed. Some error checking is done.
+
+=head2 get_parent_args OwnerClass, AttributeName -> Hash
+
+Returns the options that the parent class of C<OwnerClass> used for attribute
+C<AttributeName>.
+
=cut
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