--- name: "Type::Library" section: "3pm" platform: "linux" package: "perl-type-tiny" version: "2.010001-1" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/Type::Library" --- # Type::Library(3pm) tiny, yet Moo(se)-compatible type libraries ## NAME Type::Library - tiny, yet Moo(se)-compatible type libraries ## SYNOPSIS ``` package Types::Mine { use Scalar::Util qw(looks_like_number); use Type::Library -base; use Type::Tiny; my $NUM = "Type::Tiny"->new( name => "Number", constraint => sub { looks_like_number($_) }, message => sub { "$_ ain't a number" }, ); __PACKAGE__->meta->add_type($NUM); __PACKAGE__->meta->make_immutable; } package Ermintrude { use Moo; use Types::Mine qw(Number); has favourite_number => (is => "ro", isa => Number); } package Bullwinkle { use Moose; use Types::Mine qw(Number); has favourite_number => (is => "ro", isa => Number); } package Maisy { use Mouse; use Types::Mine qw(Number); has favourite_number => (is => "ro", isa => Number); } ``` ## STATUS This module is covered by the Type-Tiny stability policy. ## DESCRIPTION Type::Library is a tiny class for creating MooseX::Types-like type libraries which are compatible with Moo, Moose and Mouse. If you're reading this because you want to create a type library, then you're probably better off reading Type::Tiny::Manual::Libraries. ### Type library methods A type library is a singleton class. Use the `"meta"` method to get a blessed object which other methods can get called on. For example: ``` Types::Mine->meta->add_type($foo); ``` - add\_type($type) or add\_type(%opts) Add a type to the library. If `%opts` is given, then this method calls `"Type::Tiny->new(%opts)"` first, and adds the resultant type. Adding a type named "Foo" to the library will automatically define four functions in the library's namespace: - "Foo" Returns the Type::Tiny object. - is\_Foo($value) Returns true iff `$value` passes the type constraint. - assert\_Foo($value) Returns `$value` iff `$value` passes the type constraint. Dies otherwise. - to\_Foo($value) Coerces the value to the type. - get\_type($name) Gets the `"Type::Tiny"` object corresponding to the name. - has\_type($name) Boolean; returns true if the type exists in the library. - "type\_names" List all types defined by the library. - add\_coercion($c) or add\_coercion(%opts) Add a standalone coercion to the library. If `%opts` is given, then this method calls `"Type::Coercion->new(%opts)"` first, and adds the resultant coercion. Adding a coercion named "FooFromBar" to the library will automatically define a function in the library's namespace: - "FooFromBar" Returns the Type::Coercion object. - get\_coercion($name) Gets the `"Type::Coercion"` object corresponding to the name. - has\_coercion($name) Boolean; returns true if the coercion exists in the library. - "coercion\_names" List all standalone coercions defined by the library. - import(@args) Type::Library-based libraries are exporters. - "make\_immutable" Prevents new type constraints and coercions from being added to the library, and also calls `"$type->coercion->freeze"` on every type constraint in the library. (Prior to Type::Library v2, `"make_immutable"` would call `"$type->coercion->freeze"` on every constraint in the library, but not prevent new type constraints and coercions from being added to the library.) ### Type library exported functions Type libraries are exporters. For the purposes of the following examples, assume that the `"Types::Mine"` library defines types `"Number"` and `"String"`. ``` # Exports nothing. # use Types::Mine; # Exports a function "String" which is a constant returning # the String type constraint. # use Types::Mine qw( String ); # Exports both String and Number as above. # use Types::Mine qw( String Number ); # Same. # use Types::Mine qw( :types ); # Exports "coerce_String" and "coerce_Number", as well as any other # coercions # use Types::Mine qw( :coercions ); # Exports a sub "is_String" so that "is_String($foo)" is equivalent # to "String->check($foo)". # use Types::Mine qw( is_String ); # Exports "is_String" and "is_Number". # use Types::Mine qw( :is ); # Exports a sub "assert_String" so that "assert_String($foo)" is # equivalent to "String->assert_return($foo)". # use Types::Mine qw( assert_String ); # Exports "assert_String" and "assert_Number". # use Types::Mine qw( :assert ); # Exports a sub "to_String" so that "to_String($foo)" is equivalent # to "String->coerce($foo)". # use Types::Mine qw( to_String ); # Exports "to_String" and "to_Number". # use Types::Mine qw( :to ); # Exports "String", "is_String", "assert_String" and "coerce_String". # use Types::Mine qw( +String ); # Exports everything. # use Types::Mine qw( :all ); ``` Type libraries automatically inherit from Exporter::Tiny; see the documentation of that module for tips and tricks importing from libraries. ### Type::Library's methods The above sections describe the characteristics of libraries built with Type::Library. The following methods are available on Type::Library itself. - "setup\_type\_library( $package, $utils, \\@extends )" Sets up a package to be a type library. `$utils` is a boolean indicating whether to import Type::Utils into the package. `@extends` is a list of existing type libraries the package should extend. ## BUGS Please report any bugs to \. ## SEE ALSO Type::Tiny::Manual. Type::Tiny, Type::Utils, Types::Standard, Type::Coercion. Moose::Util::TypeConstraints, Mouse::Util::TypeConstraints. ## AUTHOR Toby Inkster \. ## COPYRIGHT AND LICENCE This software is copyright (c) 2013-2014, 2017-2025 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.