1Type::Tiny::Manual::UsiUnsgeWritChoCnltarsisbTuitneydT(y3Pp)eer:l:TDioncyu:m:eMnatnautailo:n:UsingWithClassTiny(3)
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NAME

6       Type::Tiny::Manual::UsingWithClassTiny - use of Type::Tiny with
7       Class::Tiny
8

MANUAL

10       Class::Tiny is an even-smaller-than-Moo class builder.
11
12       Let's translate the classic Horse class from Moo to Class::Tiny.
13
14       Moo:
15
16         package Horse {
17           use Moo;
18           use Types::Standard qw( Str Num ArrayRef );
19           use namespace::autoclean;
20
21           has name       => ( is => 'ro', isa => Str, required => 1 );
22           has gender     => ( is => 'ro', isa => Str );
23           has age        => ( is => 'rw', isa => Num );
24           has children   => (
25             is       => 'ro',
26             isa      => ArrayRef,
27             default  => sub { return [] },
28           );
29         }
30
31       Class::Tiny:
32
33         package Horse {
34           use Class::Tiny qw( gender age ), {
35             name     => sub { die "name is required"; },
36             children => sub { return [] },
37           };
38           use Types::Standard qw( Str Num ArrayRef Dict Optional slurpy Any);
39           use Type::Params qw( wrap_methods compile );
40           use namespace::autoclean;
41
42           # type checks
43           wrap_methods(
44             BUILD    => [Dict[
45               name       => Str,
46               gender     => Optional[Str],
47               age        => Optional[Num],
48               children   => Optional[ArrayRef],
49               slurpy Any,
50             ]],
51             name     => [],
52             gender   => [],
53             age      => Optional[Num],
54             children => [],
55           );
56         }
57
58       What's going on here?
59
60       Well, Class::Tiny, after it has built a new object, will do this:
61
62         $self->BUILD($args);
63
64       (Technically, it calls "BUILD" not just for the current class, but for
65       all parent classes too.) We can hook onto this in order to check type
66       constraints for the constructor.
67
68       We use "wrap_methods" from Type::Params to wrap the original "BUILD"
69       method (which doesn't exist, so "wrap_methods" will just assume an
70       empty sub) with a type check for $args. The type check is just a Dict
71       that checks the class's required and optional attributes and includes
72       slurpy Any at the end to be flexible for subclasses adding new
73       attributes.
74
75       Then we wrap the "name", "gender", and "children" methods with checks
76       to make sure they're only being called as getters, and we wrap "age",
77       allowing it to be called as a setter with a Num.
78
79       There are also a couple of CPAN modules that can help you out.
80
81   Class::Tiny::ConstrainedAccessor
82       Class::Tiny::ConstrainedAccessor creates a "BUILD" and accessors that
83       enforce Type::Tiny constraints.  Attribute types are passed to
84       Class::Tiny::ConstrainedAccessor; attribute defaults are passed to
85       Class::Tiny.
86
87         package Horse {
88           use Types::Standard qw( Str Num ArrayRef );
89           use Class::Tiny::ConstrainedAccessor {
90             name     => Str,
91             gender   => Str,
92             age      => Num,
93             children => ArrayRef,
94           };
95           use Class::Tiny qw( gender age ), {
96             name     => sub { die "name is required"; },
97             children => sub { return [] },
98           };
99         }
100
101   Class::Tiny::Antlers
102       Class::Tiny::Antlers provides Moose-like syntax for Class::Tiny,
103       including support for "isa".  You do not also need to use Class::Tiny
104       itself.
105
106         package Horse {
107           use Class::Tiny::Antlers qw(has);
108           use Types::Standard qw( Str Num ArrayRef );
109           use namespace::autoclean;
110
111           has name       => (
112             is        => 'ro',
113             isa       => Str,
114             default   => sub { die "name is required" },
115           );
116           has gender     => ( is => 'ro',    isa => Str );
117           has age        => ( is => 'rw',    isa => Num );
118           has children   => (
119             is        => 'ro',
120             isa       => ArrayRef,
121             default   => sub { return [] },
122           );
123         }
124

NEXT STEPS

126       Here's your next step:
127
128       •   Type::Tiny::Manual::UsingWithOther
129
130           Using Type::Tiny with Class::InsideOut, Params::Check, and
131           Object::Accessor.
132

AUTHOR

134       Toby Inkster <tobyink@cpan.org>.
135

137       This software is copyright (c) 2013-2014, 2017-2021 by Toby Inkster.
138
139       This is free software; you can redistribute it and/or modify it under
140       the same terms as the Perl 5 programming language system itself.
141

DISCLAIMER OF WARRANTIES

143       THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
144       WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
145       MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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149perl v5.34.0                      2022T-y0p1e-:2:1Tiny::Manual::UsingWithClassTiny(3)
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