* Class::MOP::Class
- fixing minor meta-circularity issue with &meta, it
is now more useful for subclasses
+ - &compute_all_applicable_attributes now just returns
+ the attribute meta-object, rather than the HASH ref
+ since all the same info can be gotten from the
+ attribute meta-object itself
+ - updated docs & tests to reflect
* examples/
- adjusting code to use the &Class::MOP::Class::meta
# create a scalar ref to use as
# the inside-out instance
my $instance = \(my $var);
- foreach my $attr (map { $_->{attribute} } $class->compute_all_applicable_attributes()) {
+ foreach my $attr ($class->compute_all_applicable_attributes()) {
# if the attr has an init_arg, use that, otherwise,
# use the attributes name itself as the init_arg
my $init_arg = $attr->has_init_arg() ? $attr->init_arg() : $attr->name;
sub construct_instance {
my ($class, %params) = @_;
my $instance = {};
- foreach my $attr (map { $_->{attribute} } $class->compute_all_applicable_attributes()) {
+ foreach my $attr ($class->compute_all_applicable_attributes()) {
# if the attr has an init_arg, use that, otherwise,
# use the attributes name itself as the init_arg
my $init_arg = $attr->has_init_arg() ? $attr->init_arg() : $attr->name;
|| confess "You cannot declare an accessor and reader and/or writer functions"
if exists $options{accessor};
- bless $class->meta->construct_instance(name => $name, %options) => $class;
+ bless $class->meta->construct_instance(name => $name, %options) => blessed($class) || $class;
});
1;
my $class = shift;
my $package_name = shift;
(defined $package_name && $package_name)
- || confess "You must pass a package name";
+ || confess "You must pass a package name";
+ # make sure the package name is not blessed
+ $package_name = blessed($package_name) || $package_name;
return $METAS{$package_name} if exists $METAS{$package_name};
$METAS{$package_name} = $class->construct_class_instance($package_name, @_);
}
return $meta;
}
-# Instance Construction
+# Instance Construction & Cloning
+
sub construct_instance {
my ($class, %params) = @_;
my $instance = {};
- foreach my $attr (map { $_->{attribute} } $class->compute_all_applicable_attributes()) {
- # if the attr has an init_arg, use that, otherwise,
- # use the attributes name itself as the init_arg
+ foreach my $attr ($class->compute_all_applicable_attributes()) {
my $init_arg = $attr->has_init_arg() ? $attr->init_arg() : $attr->name;
# try to fetch the init arg from the %params ...
my $val;
$val = $params{$init_arg} if exists $params{$init_arg};
# if nothing was in the %params, we can use the
# attribute's default value (if it has one)
- $val ||= $attr->default($instance) if $attr->has_default();
- # now add this to the instance structure
+ $val ||= $attr->default($instance) if $attr->has_default();
$instance->{$attr->name} = $val;
}
return $instance;
}
+sub clone_instance {
+ my ($class, $self, %params) = @_;
+ (blessed($self))
+ || confess "You can only clone instances, \$self is not a blessed instance";
+ # NOTE:
+ # this should actually do a deep clone
+ # instead of this cheap hack. I will
+ # add that in later.
+ # (use the Class::Cloneable::Util code)
+ my $clone = { %{$self} };
+ foreach my $attr ($class->compute_all_applicable_attributes()) {
+ my $init_arg = $attr->has_init_arg() ? $attr->init_arg() : $attr->name;
+ # try to fetch the init arg from the %params ...
+ $clone->{$attr->name} = $params{$init_arg}
+ if exists $params{$init_arg};
+ }
+ return $clone;
+}
+
# Informational
sub name { $_[0]->{'$:package'} }
foreach my $attr_name ($meta->get_attribute_list()) {
next if exists $seen_attr{$attr_name};
$seen_attr{$attr_name}++;
- push @attrs => {
- name => $attr_name,
- class => $class,
- attribute => $meta->get_attribute($attr_name)
- };
+ push @attrs => $meta->get_attribute($attr_name);
}
}
return @attrs;
=back
-=head2 Object instance construction
-
-This method is used to construct an instace structure suitable for
-C<bless>-ing into your package of choice. It works in conjunction
-with the Attribute protocol to collect all applicable attributes.
+=head2 Object instance construction and cloning
-This method is B<entirely optional>, it is up to you whether you want
-to use it or not.
+These methods are B<entirely optional>, it is up to you whether you want
+to use them or not.
=over 4
=item B<construct_instance (%params)>
+This method is used to construct an instace structure suitable for
+C<bless>-ing into your package of choice. It works in conjunction
+with the Attribute protocol to collect all applicable attributes.
+
This will construct and instance using a HASH ref as storage
(currently only HASH references are supported). This will collect all
the applicable attributes and layout out the fields in the HASH ref,
in C<%params> or any default value or initializer found in the
attribute meta-object.
+=item B<clone_instance($instance, %params)>
+
+This method is a compliment of C<construct_instance> (which means if
+you override C<construct_instance>, you need to override this one too).
+
+This method will clone the C<$instance> structure created by the
+C<construct_instance> method, and apply any C<%params> passed to it
+to change the attribute values. The structure returned is (like with
+C<construct_instance>) an unC<bless>ed HASH reference, it is your
+responsibility to then bless this cloned structure into the right
+class.
+
=back
=head2 Informational
=item B<compute_all_applicable_attributes>
-This will traverse the inheritance heirachy and return a list of HASH
-references for all the applicable attributes for this class. The HASH
-references will contain the following information; the attribute name,
-the class which the attribute is associated with and the actual
-attribute meta-object.
+This will traverse the inheritance heirachy and return a list of all
+the applicable attributes for this class. It does not construct a
+HASH reference like C<compute_all_applicable_methods> because all
+that same information is discoverable through the attribute
+meta-object itself.
=back
sub import {
shift;
- my $metaclass = shift;
+ my $metaclass = shift || 'Class::MOP::Class';
my %options = @_;
my $package = caller();
});
}
+=pod
+
+NOTES
+
+Okay, the metaclass constraint issue is a bit of a PITA.
+
+Especially in the context of MI, where we end up with an
+explosion of metaclasses.
+
+SOOOO
+
+Instead of auto-composing metaclasses using inheritance
+(which is problematic at best, and totally wrong at worst,
+especially in the light of methods of Class::MOP::Class
+which are overridden by subclasses (try to figure out how
+LazyClass and InsideOutClass could be composed, it is not
+even possible)) we use a trait model.
+
+It will be similar to Class::Trait, except that there is
+no such thing as a trait, a class isa trait and a trait
+isa class, more like Scala really.
+
+This way we get several benefits:
+
+1) Classes can be composed like traits, and it Just Works.
+
+2) Metaclasses can be composed this way too :)
+
+3) When solving the metaclass constraint, we create an
+ anon-metaclass, and compose the parent's metaclasses
+ into it. This allows for conflict checking trait-style
+ which should inform us of any issues right away.
+
+Misc. Details:
+
+Class metaclasses must be composed, but so must any
+associated Attribute and Method metaclasses. However, this
+is not always relevant since I should be able to create a
+class which has lazy attributes, and then create a subclass
+of that class whose attributes are not lazy.
+
+
+=cut
+
1;
__END__
=head1 DESCRIPTION
+This is a pragma to make it easier to use a specific metaclass
+and it's
+
=head1 AUTHOR
Stevan Little E<lt>stevan@iinteractive.comE<gt>
use strict;
use warnings;
-use Test::More tests => 30;
+use Test::More tests => 33;
use Test::Exception;
BEGIN {
isa_ok($meta, 'Class::MOP::Class');
is_deeply(
- [ sort { $a->{name} cmp $b->{name} } $meta->compute_all_applicable_attributes() ],
+ [ sort { $a->name cmp $b->name } $meta->compute_all_applicable_attributes() ],
[
- {
- name => '$bar',
- class => 'Bar',
- attribute => $BAR_ATTR
- },
- {
- name => '$baz',
- class => 'Baz',
- attribute => $BAZ_ATTR
- },
- {
- name => '$foo',
- class => 'Foo',
- attribute => $FOO_ATTR
- },
+ $BAR_ATTR,
+ $BAZ_ATTR,
+ $FOO_ATTR,
],
'... got the right list of applicable attributes for Baz');
+
+ is_deeply(
+ [ map { $_->associated_class } sort { $a->name cmp $b->name } $meta->compute_all_applicable_attributes() ],
+ [ Bar->meta, Baz->meta, Foo->meta ],
+ '... got the right list of associated classes from the applicable attributes for Baz');
my $attr;
lives_ok {
ok(!$meta->has_method('set_baz'), '... a writer has been removed');
is_deeply(
- [ sort { $a->{name} cmp $b->{name} } $meta->compute_all_applicable_attributes() ],
+ [ sort { $a->name cmp $b->name } $meta->compute_all_applicable_attributes() ],
[
- {
- name => '$bar',
- class => 'Bar',
- attribute => $BAR_ATTR
- },
- {
- name => '$foo',
- class => 'Foo',
- attribute => $FOO_ATTR
- },
+ $BAR_ATTR,
+ $FOO_ATTR,
],
'... got the right list of applicable attributes for Baz');
+ is_deeply(
+ [ map { $_->associated_class } sort { $a->name cmp $b->name } $meta->compute_all_applicable_attributes() ],
+ [ Bar->meta, Foo->meta ],
+ '... got the right list of associated classes from the applicable attributes for Baz');
+
{
my $attr;
lives_ok {
}
is_deeply(
- [ sort { $a->{name} cmp $b->{name} } $meta->compute_all_applicable_attributes() ],
+ [ sort { $a->name cmp $b->name } $meta->compute_all_applicable_attributes() ],
[
- {
- name => '$foo',
- class => 'Foo',
- attribute => $FOO_ATTR
- },
+ $FOO_ATTR,
],
'... got the right list of applicable attributes for Baz');
+ is_deeply(
+ [ map { $_->associated_class } sort { $a->name cmp $b->name } $meta->compute_all_applicable_attributes() ],
+ [ Foo->meta ],
+ '... got the right list of associated classes from the applicable attributes for Baz');
+
}
{
package Foo;
- use Class::MOP 'meta';
+ use metaclass;
Foo->meta->add_attribute(Perl6Attribute->new('$.foo'));
Foo->meta->add_attribute(Perl6Attribute->new('@.bar'));
projects / gitmo/Class-MOP.git / commitdiff