Type::Tiny::Manual::UsingWithMoose - how to use Type::Tiny with Moose
First read Type::Tiny::Manual::Moo, Type::Tiny::Manual::Moo2, and Type::Tiny::Manual::Moo3. Everything in those parts of the manual should work exactly the same in Moose.
This part of the manual will focus on Moose-specifics.
Moose does have a built-in type constraint system which is fairly convenient to use, but there are several reasons you should consider using Type::Tiny instead.
Type::Tiny type constraints will usually be faster than Moose built-ins. Even without Type::Tiny::XS installed, Type::Tiny usually produces more efficient inline code than Moose. Coercions will usually be a lot faster.
Type::Tiny provides helpful methods like where and plus_coercions that allow type constraints and coercions to be easily tweaked on a per-attribute basis.
where
plus_coercions
Something like this is much harder to do with plain Moose types:
has name => ( is => "ro", isa => Str->plus_coercions( ArrayRef[Str], sub { join " ", @$_ }, ), coerce => 1, );
Moose tends to encourage defining coercions globally, so if you wanted one Str attribute to be able to coerce from ArrayRef[Str], then all Str attributes would coerce from ArrayRef[Str], and they'd all do that coercion in the same way. (Even if it might make sense to join by a space in some places, a comma in others, and a line break in others!)
Type::Tiny provides automatic deep coercions, so if type Xyz has a coercion, the following should "just work":
isa xyzlist => ( is => 'ro', isa => ArrayRef[Xyz], coerce => 1 );
Type::Tiny offers a wider selection of built-in types.
By using Type::Tiny, you can use the same type constraints and coercions for attributes and method parameters, in Moose and non-Moose code.
If you've used Moose::Util::TypeConstraints, you may be accustomed to using a DSL for declaring type constraints:
use Moose::Util::TypeConstraints; subtype 'Natural', as 'Int', where { $_ > 0 };
There's a module called Type::Utils that provides a very similar DSL for declaring types in Type::Library-based type libraries.
package My::Types { use Type::Library -base; use Type::Utils; use Types::Standard qw( Int ); declare 'Natural', as Int, where { $_ > 0 }; }
Personally I prefer the more object-oriented way to declare types though.
In Moose you might also declare types like this within classes and roles too. Unlike Moose, Type::Tiny doesn't keep types in a single global flat namespace, so this doesn't work quite the same with Type::Utils. It still creates the type, but it doesn't store it in any type library; the type is returned.
package My::Class { use Moose; use Type::Utils; use Types::Standard qw( Int ); my $Natural = # store type in a variable declare 'Natural', as Int, where { $_ > 0 }; has number => ( is => 'ro', isa => $Natural ); }
But really, isn't the object-oriented way cleaner?
package My::Class { use Moose; use Types::Standard qw( Int ); has number => ( is => 'ro', isa => Int->where('$_ > 0'), ); }
Types::Standard should be a drop-in replacement for MooseX::Types. And Types::Common::Numeric and Types::Common::String should easily replace MooseX::Types::Common::Numeric and MooseX::Types::Common::String.
That said, if you do with to use a mixture of Type::Tiny and MooseX::Types, they should fit together pretty seamlessly.
use Types::Standard qw( ArrayRef ); use MooseX::Types::Common::Numeric qw( PositiveInt ); # this should just work my $list_of_nums = ArrayRef[PositiveInt]; # and this my $list_or_num = ArrayRef | PositiveInt;
-moose
If you have read this far in the manual, you will know that this is the usual way to import type constraints:
use Types::Standard qw( Int );
And the Int which is imported is a function that takes no arguments and returns the Int type constraint, which is a blessed object in the Type::Tiny class.
Int
Type::Tiny mocks the Moose::Meta::TypeConstraint API so well that most Moose and MooseX code will not be able to tell the difference.
But what if you need a real Moose::Meta::TypeConstraint object?
use Types::Standard -moose, qw( Int );
Now the Int function imported will return a genuine native Moose type constraint.
This flag is mostly a throwback from when Type::Tiny native objects didn't directly work in Moose. In 99.9% of cases, there is no reason to use it and plenty of reasons not to. (Moose native type constraints don't offer helpful methods like plus_coercions and where.)
moose_type
Another quick way to get a native Moose type constraint object from a Type::Tiny object is to call the moose_type method:
use Types::Standard qw( Int ); my $tiny_type = Int; my $moose_type = $tiny_type->moose_type;
Internally, this is what the -moose flag makes imported functions do.
Here's your next step:
Type::Tiny::Manual::UsingWithMouse
How to use Type::Tiny with Mouse, including the advantages of Type::Tiny over built-in type constraints, and Mouse-specific features.
Toby Inkster <tobyink@cpan.org>.
This software is copyright (c) 2013-2014, 2017-2019 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.
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.
To install Type::Tiny, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Type::Tiny
CPAN shell
perl -MCPAN -e shell install Type::Tiny
For more information on module installation, please visit the detailed CPAN module installation guide.