NAME

       Type::Registry - a glorified hashref for looking up type constraints

SYNOPSIS

          package Foo::Bar;

          use Type::Registry;

          my $reg = "Type::Registry"->for_me;  # a registry for Foo::Bar

          # Register all types from Types::Standard
          $reg->add_types(-Standard);

          # Register just one type from Types::XSD
          $reg->add_types(-XSD => ["NonNegativeInteger"]);

          # Register all types from MyApp::Types
          $reg->add_types("MyApp::Types");

          # Create a type alias
          $reg->alias_type("NonNegativeInteger" => "Count");

          # Look up a type constraint
          my $type = $reg->lookup("ArrayRef[Count]");

          $type->check([1, 2, 3.14159]);  # croaks

       Alternatively:

          package Foo::Bar;

          use Type::Registry qw( t );

          # Register all types from Types::Standard
          t->add_types(-Standard);

          # Register just one type from Types::XSD
          t->add_types(-XSD => ["NonNegativeInteger"]);

          # Register all types from MyApp::Types
          t->add_types("MyApp::Types");

          # Create a type alias
          t->alias_type("NonNegativeInteger" => "Count");

          # Look up a type constraint
          my $type = t("ArrayRef[Count]");

          $type->check([1, 2, 3.14159]);  # croaks

STATUS

       Type::Registry (and Type::Parser) is currently a pretty isolated part of this
       distribution. It seems like something that would be useful, but it's not heavily
       integrated with everything else. In particular, if you do:

          use Type::Registry qw(t);
          use Types::Standard -types;

       Then the "Str", "Num", etc keywords imported from Types::Standard will work fine, but
       "t->lookup("Str")" and "t->lookup("Num")" will fail, because importing types from a
       library does not automatically add them to your registry.

       Clearly some kind of integration is desirable between Type::Registry and Type::Library,
       but exactly what form that will take is still to be decided.

       So if you decide to use Type::Registry, be aware of its somewhat experimental status. It's
       not likely to disappear completely, but there may be changes ahead.

DESCRIPTION

       A type registry is basically just a hashref mapping type names to type constraint objects.

   Constructors
       "new"
           Create a new glorified hashref.

       "for_class($class)"
           Create or return the existing glorified hashref associated with the given class.

       "for_me"
           Create or return the existing glorified hashref associated with the caller.

   Methods
       "add_types(@libraries)"
           The libraries list is treated as an "optlist" (a la Data::OptList).

           Strings are the names of type libraries; if the first character is a hyphen, it is
           expanded to the "Types::" prefix. If followed by an arrayref, this is the list of
           types to import from that library.  Otherwise, imports all types from the library.

              use Type::Registry qw(t);

              t->add_types(-Standard);  # OR: t->add_types("Types::Standard");

              t->add_types(
                 -TypeTiny => ['HashLike'],
                 -Standard => ['HashRef' => { -as => 'RealHash' }],
              );

       "alias_type($oldname, $newname)"
           Create an alias for an existing type.

       "simple_lookup($name)"
           Look up a type in the registry by name.

           Returns undef if not found.

       "lookup($name)"
           Look up by name, with a DSL.

              t->lookup("Int|ArrayRef[Int]")

           The DSL can be summed up as:

              X               type from this registry
              My::Lib::X      type from a type library
              ~X              complementary type
              X | Y           union
              X & Y           intersection
              X[...]          parameterized type
              slurpy X        slurpy type
              Foo::Bar::      class type

           Croaks if not found.

       "AUTOLOAD"
           Overloaded to call "lookup".

              $registry->Str;  # like $registry->lookup("Str")

   Functions
       "t" This class can export a function "t" which acts like
           ""Type::Registry"->for_class($importing_class)".

BUGS

       Please report any bugs to <http://rt.cpan.org/Dist/Display.html?Queue=Type-Tiny>.

SEE ALSO

       Type::Library.

AUTHOR

       Toby Inkster <tobyink@cpan.org>.

COPYRIGHT AND LICENCE

       This software is copyright (c) 2013 by Toby Inkster.

       This is free software; you can redistribute it and/or modify it under the same terms as
       the Perl 5 programming language system itself.

DISCLAIMER OF WARRANTIES

       THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
       WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
       PURPOSE.