package MooseX::Types::Util;
-=head1 NAME
-
-MooseX::Types::Util - Common utility functions for the module
-
-=cut
+#ABSTRACT: Common utility functions for the distribution
use warnings;
use strict;
+use Scalar::Util 'blessed';
use base 'Exporter';
=head1 DESCRIPTION
-This package the exportable functions that many parts in
+This package the exportable functions that many parts in
L<MooseX::Types> might need.
=cut
-our @EXPORT_OK = qw( filter_tags );
+our @EXPORT_OK = qw( filter_tags has_available_type_export );
=head1 FUNCTIONS
return \%tags, \@other;
}
-=head1 SEE ALSO
+=head2 has_available_type_export
-L<MooseX::Types::Moose>, L<Exporter>
+ TypeConstraint | Undef = has_available_type_export($package, $name);
+
+This function allows you to introspect if a given type export is available
+I<at this point in time>. This means that the C<$package> must have imported
+a type constraint with the name C<$name>, and it must be still in its symbol
+table.
+
+Two arguments are expected:
+
+=over 4
+
+=item $package
+
+The name of the package to introspect.
+
+=item $name
+
+The name of the type export to introspect.
+
+=back
+
+B<Note> that the C<$name> is the I<exported> name of the type, not the declared
+one. This means that if you use L<Sub::Exporter>s functionality to rename an import
+like this:
-=head1 AUTHOR AND COPYRIGHT
+ use MyTypes Str => { -as => 'MyStr' };
-Robert 'phaylon' Sedlacek C<E<lt>rs@474.atE<gt>>, with many thanks to
-the C<#moose> cabal on C<irc.perl.org>.
+you would have to introspect this type like this:
+
+ has_available_type_export $package, 'MyStr';
+
+The return value will be either the type constraint that belongs to the export
+or an undefined value.
+
+=cut
+
+sub has_available_type_export {
+ my ($package, $name) = @_;
+
+ my $sub = $package->can($name)
+ or return undef;
+
+ return undef
+ unless blessed $sub && $sub->isa('MooseX::Types::EXPORTED_TYPE_CONSTRAINT');
+
+ return $sub->();
+}
+
+=head1 SEE ALSO
+
+L<MooseX::Types::Moose>, L<Exporter>
=head1 LICENSE