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6 Type::Tiny::Manual::UsingWithMouse - how to use Type::Tiny with Mouse
7
9 First read Type::Tiny::Manual::Moo, Type::Tiny::Manual::Moo2, and
10 Type::Tiny::Manual::Moo3. Everything in those parts of the manual
11 should work exactly the same in Mouse.
12 This part of the manual will focus on Mouse-specifics.
14 Overall, Type::Tiny is less well-tested with Mouse than it is with
16 Moose and Moo, but there are still a good number of test cases for
17 using Type::Tiny with Mouse, and there are no known major issues with
18 Type::Tiny's Mouse support.
19 Why Use Type::Tiny At All?
21 Mouse does have a built-in type constraint system which is fairly
22 convenient to use, but there are several reasons you should consider
23 using Type::Tiny instead.
24 • Type::Tiny provides helpful methods like "where" and
26 "plus_coercions" that allow type constraints and coercions to be
27 easily tweaked on a per-attribute basis.
28 Something like this is much harder to do with plain Mouse types:
30 has name => (
32 is => "ro",
33 isa => Str->plus_coercions(
34 ArrayRef[Str], sub { join " ", @$_ },
35 ),
36 coerce => 1,
37 );
38 Mouse tends to encourage defining coercions globally, so if you
40 wanted one Str attribute to be able to coerce from ArrayRef[Str],
41 then all Str attributes would coerce from ArrayRef[Str], and they'd
42 all do that coercion in the same way. (Even if it might make sense
43 to join by a space in some places, a comma in others, and a line
44 break in others!)
45 • Type::Tiny provides automatic deep coercions, so if type Xyz has a
47 coercion, the following should "just work":
48 has xyzlist => ( is => 'ro', isa => ArrayRef[Xyz], coerce => 1 );
50 • Type::Tiny offers a wider selection of built-in types.
52 • By using Type::Tiny, you can use the same type constraints and
54 coercions for attributes and method parameters, in Mouse and non-
55 Mouse code.
56 Type::Utils
58 If you've used Mouse::Util::TypeConstraints, you may be accustomed to
59 using a DSL for declaring type constraints:
60 use Mouse::Util::TypeConstraints;
62 subtype 'Natural',
64 as 'Int',
65 where { $_ > 0 };
66 There's a module called Type::Utils that provides a very similar DSL
68 for declaring types in Type::Library-based type libraries.
69 package My::Types {
71 use Type::Library -base;
72 use Type::Utils;
73 use Types::Standard qw( Int );
74 declare 'Natural',
76 as Int,
77 where { $_ > 0 };
78 }
79 Personally I prefer the more object-oriented way to declare types
81 though.
82 In Mouse you might also declare types like this within classes and
84 roles too. Unlike Mouse, Type::Tiny doesn't keep types in a single
85 global flat namespace, so this doesn't work quite the same with
86 Type::Utils. It still creates the type, but it doesn't store it in any
87 type library; the type is returned.
88 package My::Class {
90 use Mouse;
91 use Type::Utils;
92 use Types::Standard qw( Int );
93 my $Natural = # store type in a variable
95 declare 'Natural',
96 as Int,
97 where { $_ > 0 };
98 has number => ( is => 'ro', isa => $Natural );
100 }
101 But really, isn't the object-oriented way cleaner?
103 package My::Class {
105 use Mouse;
106 use Types::Standard qw( Int );
107 has number => (
109 is => 'ro',
110 isa => Int->where('$_ > 0'),
111 );
112 }
113 Type::Tiny and MouseX::Types
115 Types::Standard should be a drop-in replacement for MooseX::Types. And
116 Types::Common::Numeric and Types::Common::String should easily replace
117 MouseX::Types::Common::Numeric and MouseX::Types::Common::String.
118 That said, if you do with to use a mixture of Type::Tiny and
120 MouseX::Types, they should fit together pretty seamlessly.
121 use Types::Standard qw( ArrayRef );
123 use MouseX::Types::Mouse qw( Int );
124 # this should just work
126 my $list_of_nums = ArrayRef[Int];
127 # and this
129 my $list_or_num = ArrayRef | Int;
130 "-mouse" Import Parameter
132 If you have read this far in the manual, you will know that this is the
133 usual way to import type constraints:
134 use Types::Standard qw( Int );
136 And the "Int" which is imported is a function that takes no arguments
138 and returns the Int type constraint, which is a blessed object in the
139 Type::Tiny class.
140 Type::Tiny mocks the Mouse::Meta::TypeConstraint API so well that most
142 Mouse and MouseX code will not be able to tell the difference.
143 But what if you need a real Mouse::Meta::TypeConstraint object?
145 use Types::Standard -mouse, qw( Int );
147 Now the "Int" function imported will return a genuine native Mouse type
149 constraint.
150 This flag is mostly a throwback from when Type::Tiny native objects
152 didn't directly work in Mouse. In 99.9% of cases, there is no reason to
153 use it and plenty of reasons not to. (Mouse native type constraints
154 don't offer helpful methods like "plus_coercions" and "where".)
155 "mouse_type" Method
157 Another quick way to get a native Mouse type constraint object from a
158 Type::Tiny object is to call the "mouse_type" method:
159 use Types::Standard qw( Int );
161 my $tiny_type = Int;
163 my $mouse_type = $tiny_type->mouse_type;
164 Internally, this is what the "-mouse" flag makes imported functions do.
166 Type::Tiny Performance
168 Type::Tiny should run pretty much as fast as Mouse types do. This is
169 because, when possible, it will use Mouse's XS implementations of type
170 checks to do the heavy lifting.
171 There are a few type constraints where Type::Tiny prefers to do things
173 without Mouse's help though, for consistency and correctness. For
174 example, the Mouse XS implementation of Bool is... strange... it
175 accepts blessed objects that overload "bool", but only if they return
176 false. If they return true, it's a type constraint error.
177 Using Type::Tiny instead of Mouse's type constraints shouldn't make a
179 significant difference to the performance of your code.
180
182 Here's your next step:
183 • Type::Tiny::Manual::UsingWithMite
185 How to use Type::Tiny with Mite, including how to write an entire
187 Perl project using clean Moose-like code and no non-core
188 dependencies. (Not even dependencies on Mite or Type::Tiny!)
189
191 Toby Inkster <tobyink@cpan.org>.
192
194 This software is copyright (c) 2013-2014, 2017-2023 by Toby Inkster.
195 This is free software; you can redistribute it and/or modify it under
197 the same terms as the Perl 5 programming language system itself.
198
200 THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
201 WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
202 MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
203perl v5.38.0 2023-07-T2y1pe::Tiny::Manual::UsingWithMouse(3)