NAME
    MooseX::Types - Organise your Moose types in libraries

SYNOPSIS
  Library Definition
      package MyLibrary;
      use strict;

      # predeclare our own types
      use MooseX::Types 
          -declare => [qw( PositiveInt NegativeInt )];

      # import builtin types
      use MooseX::Types::Moose 'Int';

      # type definition
      subtype PositiveInt, 
          as Int, 
          where { $_ > 0 },
          message { "Int is not larger than 0" };
  
      subtype NegativeInt,
          as Int,
          where { $_ < 0 },
          message { "Int is not smaller than 0" };

      # type coercion
      coerce PositiveInt,
          from Int,
              via { 1 };

      1;

  Usage
      package Foo;
      use Moose;
      use MyLibrary qw( PositiveInt NegativeInt );

      # use the exported constants as type names
      has 'bar',
          isa    => PositiveInt,
          is     => 'rw';
      has 'baz',
          isa    => NegativeInt,
          is     => 'rw';

      sub quux {
          my ($self, $value);

          # test the value
          print "positive\n" if is_PositiveInt($value);
          print "negative\n" if is_NegativeInt($value);

          # coerce the value, NegativeInt doesn't have a coercion
          # helper, since it didn't define any coercions.
          $value = to_PositiveInt($value) or die "Cannot coerce";
      }

      1;

DESCRIPTION
    The types provided with Moose are by design global. This package helps
    you to organise and selectively import your own and the built-in types
    in libraries. As a nice side effect, it catches typos at compile-time
    too.

    However, the main reason for this module is to provide an easy way to
    not have conflicts with your type names, since the internal fully
    qualified names of the types will be prefixed with the library's name.

    This module will also provide you with some helper functions to make it
    easier to use Moose types in your code.

TYPE HANDLER FUNCTIONS
  $type
    A constant with the name of your type. It contains the type's fully
    qualified name. Takes no value, as all constants.

  is_$type
    This handler takes a value and tests if it is a valid value for this
    $type. It will return true or false.

  to_$type
    A handler that will take a value and coerce it into the $type. It will
    return a false value if the type could not be coerced.

    Important Note: This handler will only be exported for types that can do
    type coercion. This has the advantage that a coercion to a type that
    cannot hasn't defined any coercions will lead to a compile-time error.

LIBRARY DEFINITION
    A MooseX::Types is just a normal Perl module. Unlike Moose itself, it
    does not install "use strict" and "use warnings" in your class by
    default, so this is up to you.

    The only thing a library is required to do is

      use MooseX::Types -declare => \@types;

    with @types being a list of types you wish to define in this library.
    This line will install a proper base class in your package as well as
    the full set of handlers for your declared types. It will then hand
    control over to Moose::Util::TypeConstraints' "import" method to export
    the functions you will need to declare your types.

    If you want to use Moose' built-in types (e.g. for subtyping) you will
    want to

      use MooseX::Types::Moose @types;

    to import the helpers from the shipped MooseX::Types::Moose library
    which can export all types that come with Moose.

    You will have to define coercions for your types or your library won't
    export a "to_$type" coercion helper for it.

LIBRARY USAGE
    You can import the "type helpers" of a library by "use"ing it with a
    list of types to import as arguments. If you want all of them, use the
    ":all" tag. For example:

      use MyLibrary      ':all';
      use MyOtherLibrary qw( TypeA TypeB );

    MooseX::Types comes with a library of Moose' built-in types called
    MooseX::Types::Moose.

WRAPPING A LIBRARY
    You can define your own wrapper subclasses to manipulate the behaviour
    of a set of library exports. Here is an example:

      package MyWrapper;
      use strict;
      use Class::C3;
      use base 'MooseX::Types::Wrapper';

      sub coercion_export_generator {
          my $class = shift;
          my $code = $class->next::method(@_);
          return sub {
              my $value = $code->(@_);
              warn "Coercion returned undef!"
                  unless defined $value;
              return $value;
          };
      }

      1;

    This class wraps the coercion generator (e.g., "to_Int()") and warns if
    a coercion returned an undefined value. You can wrap any library with
    this:

      package Foo;
      use strict;
      use MyWrapper MyLibrary => [qw( Foo Bar )],
                    Moose     => [qw( Str Int )];

      ...
      1;

    The "Moose" library name is a special shortcut for MooseX::Types::Moose.

  Generator methods you can overload
    type_export_generator( $short, $full )
        Creates a closure returning the type's Moose::Meta::TypeConstraint
        object.

    check_export_generator( $short, $full, $undef_message )
        This creates the closure used to test if a value is valid for this
        type.

    coercion_export_generator( $short, $full, $undef_message )
        This is the closure that's doing coercions.

  Provided Parameters
    $short
        The short, exported name of the type.

    $full
        The fully qualified name of this type as Moose knows it.

    $undef_message
        A message that will be thrown when type functionality is used but
        the type does not yet exist.

METHODS
  import
    Installs the MooseX::Types::Base class into the caller and exports types
    according to the specification described in "LIBRARY DEFINITION". This
    will continue to Moose::Util::TypeConstraints' "import" method to export
    helper functions you will need to declare your types.

  type_export_generator
    Generate a type export, e.g. "Int()". This will return either a
    Moose::Meta::TypeConstraint object, or alternatively a
    MooseX::Types::UndefinedType object if the type was not yet defined.

  coercion_export_generator
    This generates a coercion handler function, e.g. "to_Int($value)".

  check_export_generator
    Generates a constraint check closure, e.g. "is_Int($value)".

CAVEATS
    A library makes the types quasi-unique by prefixing their names with (by
    default) the library package name. If you're only using the type handler
    functions provided by MooseX::Types, you shouldn't ever have to use a
    type's actual full name.

SEE ALSO
    Moose, Moose::Util::TypeConstraints, MooseX::Types::Moose

AUTHOR AND COPYRIGHT
    Robert 'phaylon' Sedlacek "<rs@474.at>", with many thanks to the
    "#moose" cabal on "irc.perl.org".

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