Provided by: libmoosex-types-perl_0.41-1_all bug

NAME

       MooseX::Types - Organise your Moose types in libraries

VERSION

       version 0.41

SYNOPSIS

   Library Definition
         package MyLibrary;

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

         # import builtin types
         use MooseX::Types::Moose qw/Int HashRef/;

         # 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 };

         # with parameterized constraints.

         subtype ArrayRefOfPositiveInt,
           as ArrayRef[PositiveInt];

         subtype ArrayRefOfAtLeastThreeNegativeInts,
           as ArrayRef[NegativeInt],
           where { scalar(@$_) > 2 };

         subtype LotsOfInnerConstraints,
           as ArrayRef[ArrayRef[HashRef[Int]]];

         # with TypeConstraint Unions

         subtype StrOrArrayRef,
           as Str|ArrayRef;

         # class types

         class_type 'DateTime';

         # or better

         class_type MyDateTime, { class => 'DateTime' };

         coerce MyDateTime,
           from HashRef,
           via { DateTime->new(%$_) };

         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 type system provided by Moose effectively makes all of its builtin type global, as are
       any types you declare with Moose. This means that every module that declares a type named
       "PositiveInt" is sharing the same type object. This can be a problem when different parts
       of the code base want to use the same name for different things.

       This package lets you declare types using short names, but behind the scenes it namespaces
       all your type declarations, effectively prevent name clashes between packages.

       This is done by creating a type library module like "MyApp::Types" and then importing
       types from that module into other modules.

       As a side effect, the declaration mechanism allows you to write type names as barewords
       (really function calls), which catches typos in names at compile time rather than run
       time.

       This module also provides some helper functions for using Moose types outside of attribute
       declarations.

       If you mix string-based names with types created by this module, it will warn, with a few
       exceptions. If you are declaring a "class_type()" or "role_type()" within your type
       library, or if you use a fully qualified name like "MyApp::Foo".

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.

       Note that you currently cannot define types containing "::", since exporting would be a
       problem.

       You also don't need to use "warnings" and "strict", since the definition of a library
       automatically exports those.

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.

       The exporting mechanism is, since version 0.5, implemented via a wrapper around
       Sub::Exporter. This means you can do something like this:

         use MyLibrary TypeA => { -as => 'MyTypeA' },
                       TypeB => { -as => 'MyTypeB' };

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 has not defined any coercions will
       lead to a compile-time error.

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 MRO::Compat;
         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.

RECURSIVE SUBTYPES

       As of version 0.08, Moose::Types has experimental support for Recursive subtypes.  This
       will allow:

           subtype Tree() => as HashRef[Str|Tree];

       Which validates things like:

           {key=>'value'};
           {key=>{subkey1=>'value', subkey2=>'value'}}

       And so on.  This feature is new and there may be lurking bugs so don't be afraid to hunt
       me down with patches and test cases if you have trouble.

NOTES REGARDING TYPE UNIONS

       MooseX::Types uses MooseX::Types::TypeDecorator to do some overloading which generally
       allows you to easily create union types:

         subtype StrOrArrayRef,
             as Str|ArrayRef;

       As with parameterized constraints, this overloading extends to modules using the types you
       define in a type library.

         use Moose;
         use MooseX::Types::Moose qw(HashRef Int);

         has 'attr' => ( isa => HashRef | Int );

       And everything should just work as you'd think.

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.

   create_arged_type_constraint ($name, @args)
       Given a String $name with @args find the matching type constraint and parameterize it with
       @args.

   create_base_type_constraint ($name)
       Given a String $name, find the matching type constraint.

   create_type_decorator ($type_constraint)
       Given a $type_constraint, return a lightweight MooseX::Types::TypeDecorator instance.

   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

       The following are lists of gotchas and their workarounds for developers coming from the
       standard string based type constraint names

   Uniqueness
       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.

   Argument separation ('=>' versus ',')
       The perlop manpage has this to say about the '=>' operator: "The => operator is a synonym
       for the comma, but forces any word (consisting entirely of word characters) to its left to
       be interpreted as a string (as of 5.001). This includes words that might otherwise be
       considered a constant or function call."

       Due to this stringification, the following will NOT work as you might think:

         subtype StrOrArrayRef => as Str | ArrayRef;

       The "StrOrArrayRef" type will have its stringification activated -- this causes the
       subtype to not be created.  Since the bareword type constraints are not strings you really
       should not try to treat them that way.  You will have to use the ',' operator instead.
       The authors of this package realize that all the Moose documentation and examples nearly
       uniformly use the '=>' version of the comma operator and this could be an issue if you are
       converting code.

       Patches welcome for discussion.

   Compatibility with Sub::Exporter
       If you want to use Sub::Exporter with a Type Library, you need to make sure you export all
       the type constraints declared AS WELL AS any additional export targets. For example if you
       do:

         package TypeAndSubExporter;

         use MooseX::Types::Moose qw(Str);
         use MooseX::Types -declare => [qw(MyStr)];
         use Sub::Exporter -setup => { exports => [qw(something)] };

         subtype MyStr, as Str;

         sub something {
             return 1;
         }

         # then in another module ...

         package Foo;
         use TypeAndSubExporter qw(MyStr);

       You'll get a ""MyStr" is not exported by the TypeAndSubExporter module" error.  It can be
       worked around by:

         - use Sub::Exporter -setup => { exports => [ qw(something) ] };
         + use Sub::Exporter -setup => { exports => [ qw(something MyStr) ] };

       This is a workaround and I am exploring how to make these modules work better together.  I
       realize this workaround will lead a lot of duplication in your export declarations and
       will be onerous for large type libraries.  Patches and detailed test cases welcome. See
       the tests directory for a start on this.

COMBINING TYPE LIBRARIES

       You may want to combine a set of types for your application with other type libraries,
       like MooseX::Types::Moose or MooseX::Types::Common::String.

       The MooseX::Types::Combine module provides a simple API for combining a set of type
       libraries together.

SEE ALSO

       Moose, Moose::Util::TypeConstraints, MooseX::Types::Moose, Sub::Exporter

ACKNOWLEDGEMENTS

       Many thanks to the "#moose" cabal on "irc.perl.org".

AUTHOR

       Robert "phaylon" Sedlacek <rs@474.at>

COPYRIGHT AND LICENSE

       This software is copyright (c) 2007 by Robert "phaylon" Sedlacek.

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

CONTRIBUTORS

       •   Dave Rolsky <autarch@urth.org>

       •   Florian Ragwitz <rafl@debian.org>

       •   Graham Knop <haarg@haarg.org>

       •   Hans Dieter Pearcey <hdp@weftsoar.net>

       •   Jesse Luehrs <doy@tozt.net>

       •   John Napiorkowski <jjnapiork@cpan.org>

       •   Justin Hunter <justin.d.hunter@gmail.com>

       •   Karen Etheridge <ether@cpan.org>

       •   Kent Fredric <kentfredric@gmail.com>

       •   Matt S Trout <mst@shadowcat.co.uk>

       •   Paul Fenwick <pjf@perltraining.com.au>

       •   Rafael Kitover <rkitover@cpan.org>

       •   Robert 'phaylon' Sedlacek <phaylon@cpan.org>

       •   Tomas Doran (t0m) <bobtfish@bobtfish.net>

       •   matthewt <matthewt@3efe9002-19ed-0310-8735-a98156148065>