NAME
    Object::InterfaceType - the Go lang Interface style duck type checker

SYNOPSIS
      use Object::InterfaceType;

      # create interface type check function
      interface_type stringify => ['as_string'];
      is_stringify(URI->new) ? 'ok' : 'ng';

      # get interface type code reference
      my $is_stringify = interface_type ['as_string'];
      $is_stringify->(URI->new) ? 'ok' : 'ng';

DESCRIPTION
    Object::InterfaceType is Go lang Interface style duck type checker.

    This module export is interface_type function.

    It is useful when you receive an object with a specific method. you can
    the recyclable duck type check can be performed.

    Object::InterfaceType is using Exporter, export of interface_type can be
    controlled.

      use Object::InterfaceType ();
      Object::InterfaceType::interface_type stringify => ['as_string'];
      is_stringify(URI->new) ? 'ok' : 'ng';

FUNCTION SPEC
  interface_type $typename => \@methods
    $typename added prefix "is_" is the function name, it creates to current
    package.

      interface_type stringify => [qw/ new as_string /];

    This created function is used as follows.

      my $uri = URI->new;
      if (is_stringify($uri)) {
          say '$uri is stringify object';
      }

    1 is returned by an object with "new" and "is_stringify" method. "undef"
    returns in the other object.

  my $check_code_reference = interface_type \@methods
    $typename is omissible. in that case, the reference of the code to check
    is returned, without performing creation of a function.

      my $is_stringify = interface_type [qw/ new as_string /];

      my $uri = URI->new;
      if ($is_stringify->($uri)) {
          say '$uri is stringify object';
      }

TODO
    includable interface is unsupported.

    specification proposal

      interface_type stringify => [qw/ as_string /];
      my $is_dump = interface_type [qw/ as_dump /];

      # including stringify and $is_dump
      interface_type dump_with_syringify => [
          'new', \&is_stringify, $is_dump
      ];

AUTHOR
    Kazuhiro Osawa <yappo <at> shibuya <döt> pl>

SEE ALSO
    <http://golang.org/doc/go_spec.html#Interface_types>

LICENSE
    This library is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

