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|
package Moose::Meta::TypeConstraint::DuckType;
use strict;
use warnings;
use metaclass;
use Scalar::Util 'blessed';
use List::MoreUtils qw(all);
use Moose::Util 'english_list';
use Moose::Util::TypeConstraints ();
our $VERSION = '1.09';
$VERSION = eval $VERSION;
our $AUTHORITY = 'cpan:STEVAN';
use base 'Moose::Meta::TypeConstraint';
__PACKAGE__->meta->add_attribute('methods' => (
accessor => 'methods',
));
sub new {
my ( $class, %args ) = @_;
$args{parent} = Moose::Util::TypeConstraints::find_type_constraint('Object');
my $self = $class->_new(\%args);
$self->compile_type_constraint()
unless $self->_has_compiled_type_constraint;
return $self;
}
sub equals {
my ( $self, $type_or_name ) = @_;
my $other = Moose::Util::TypeConstraints::find_type_constraint($type_or_name);
return unless $other->isa(__PACKAGE__);
my @self_methods = sort @{ $self->methods };
my @other_methods = sort @{ $other->methods };
return unless @self_methods == @other_methods;
while ( @self_methods ) {
my $method = shift @self_methods;
my $other_method = shift @other_methods;
return unless $method eq $other_method;
}
return 1;
}
sub constraint {
my $self = shift;
my @methods = @{ $self->methods };
return sub {
my $obj = shift;
return all { $obj->can($_) } @methods
};
}
sub _compile_hand_optimized_type_constraint {
my $self = shift;
my @methods = @{ $self->methods };
sub {
my $obj = shift;
return blessed($obj)
&& blessed($obj) ne 'Regexp'
&& all { $obj->can($_) } @methods;
};
}
sub create_child_type {
my ($self, @args) = @_;
return Moose::Meta::TypeConstraint->new(@args, parent => $self);
}
sub get_message {
my $self = shift;
my ($value) = @_;
if ($self->has_message) {
return $self->SUPER::get_message(@_);
}
my @methods = grep { !$value->can($_) } @{ $self->methods };
my $class = blessed $value;
return $class
. " is missing methods "
. english_list(map { "'$_'" } @methods);
}
1;
__END__
=pod
=head1 NAME
Moose::Meta::TypeConstraint::DuckType - Type constraint for duck typing
=head1 DESCRIPTION
This class represents type constraints based on an enumerated list of
required methods.
=head1 INHERITANCE
C<Moose::Meta::TypeConstraint::DuckType> is a subclass of
L<Moose::Meta::TypeConstraint>.
=head1 METHODS
=over 4
=item B<< Moose::Meta::TypeConstraint::DuckType->new(%options) >>
This creates a new duck type constraint based on the given
C<%options>.
It takes the same options as its parent, with several
exceptions. First, it requires an additional option, C<methods>. This
should be an array reference containing a list of required method
names. Second, it automatically sets the parent to the C<Object> type.
Finally, it ignores any provided C<constraint> option. The constraint
is generated automatically based on the provided C<methods>.
=item B<< $constraint->methods >>
Returns the array reference of required methods provided to the
constructor.
=item B<< $constraint->create_child_type >>
This returns a new L<Moose::Meta::TypeConstraint> object with the type
as its parent.
Note that it does I<not> return a C<Moose::Meta::TypeConstraint::DuckType>
object!
=back
=head1 BUGS
See L<Moose/BUGS> for details on reporting bugs.
=head1 AUTHOR
Chris Prather E<lt>chris@prather.orgE<gt>
Shawn M Moore E<lt>sartak@gmail.comE<gt>
=head1 COPYRIGHT AND LICENSE
Copyright 2006-2010 by Infinity Interactive, Inc.
L<http://www.iinteractive.com>
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut
|
