1 package Moose::Meta::TypeConstraint::DuckType;
8 use Scalar::Util 'blessed';
9 use List::MoreUtils qw(all);
10 use Moose::Util 'english_list';
12 use Moose::Util::TypeConstraints ();
14 use base 'Moose::Meta::TypeConstraint';
16 __PACKAGE__->meta->add_attribute('methods' => (
17 accessor => 'methods',
25 "Scalar::Util::blessed($val)"
26 . qq{&& Scalar::Util::blessed($val) ne 'Regexp'}
27 . "&& &List::MoreUtils::all( sub { $val->can(\$_) }, "
28 . ( join ', ', map { B::perlstring($_) } @{ $self->methods } ) . ' )';
32 my ( $class, %args ) = @_;
35 = Moose::Util::TypeConstraints::find_type_constraint('Object');
37 my @methods = @{ $args{methods} };
38 $args{constraint} = sub {
39 blessed( $_[0] ) ne 'Regexp'
40 && all { $_[0]->can($_) } @methods;
43 $args{inlined} = $inliner;
45 my $self = $class->_new(\%args);
47 $self->compile_type_constraint()
48 unless $self->_has_compiled_type_constraint;
54 my ( $self, $type_or_name ) = @_;
56 my $other = Moose::Util::TypeConstraints::find_type_constraint($type_or_name);
58 return unless $other->isa(__PACKAGE__);
60 my @self_methods = sort @{ $self->methods };
61 my @other_methods = sort @{ $other->methods };
63 return unless @self_methods == @other_methods;
65 while ( @self_methods ) {
66 my $method = shift @self_methods;
67 my $other_method = shift @other_methods;
69 return unless $method eq $other_method;
78 my @methods = @{ $self->methods };
82 return all { $obj->can($_) } @methods
86 sub create_child_type {
87 my ($self, @args) = @_;
88 return Moose::Meta::TypeConstraint->new(@args, parent => $self);
95 if ($self->has_message) {
96 return $self->SUPER::get_message(@_);
99 my @methods = grep { !$value->can($_) } @{ $self->methods };
100 my $class = blessed $value;
102 . " is missing methods "
103 . english_list(map { "'$_'" } @methods);
108 # ABSTRACT: Type constraint for duck typing
116 This class represents type constraints based on an enumerated list of
121 C<Moose::Meta::TypeConstraint::DuckType> is a subclass of
122 L<Moose::Meta::TypeConstraint>.
128 =item B<< Moose::Meta::TypeConstraint::DuckType->new(%options) >>
130 This creates a new duck type constraint based on the given
133 It takes the same options as its parent, with several
134 exceptions. First, it requires an additional option, C<methods>. This
135 should be an array reference containing a list of required method
136 names. Second, it automatically sets the parent to the C<Object> type.
138 Finally, it ignores any provided C<constraint> option. The constraint
139 is generated automatically based on the provided C<methods>.
141 =item B<< $constraint->methods >>
143 Returns the array reference of required methods provided to the
146 =item B<< $constraint->create_child_type >>
148 This returns a new L<Moose::Meta::TypeConstraint> object with the type
151 Note that it does I<not> return a C<Moose::Meta::TypeConstraint::DuckType>
158 See L<Moose/BUGS> for details on reporting bugs.