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1 | package MooseX::TypeLibrary; |
2 | |
3 | =head1 NAME |
4 | |
5 | MooseX::TypeLibrary - Organise your Moose types in libraries |
6 | |
7 | =cut |
8 | |
9 | use warnings; |
10 | use strict; |
11 | |
12 | use Sub::Uplevel; |
13 | use Moose::Util::TypeConstraints; |
14 | use MooseX::TypeLibrary::Base; |
15 | use Sub::Install qw( install_sub ); |
16 | use namespace::clean; |
17 | |
18 | our $VERSION = 0.01; |
19 | |
20 | my $UndefMsg = q{Action for type '%s' not yet defined in library '%s'}; |
21 | |
22 | =head1 SYNOPSIS |
23 | |
24 | # |
25 | # Library Definition |
26 | # |
27 | package MyLibrary; |
28 | use strict; |
29 | |
30 | # predeclare our own types |
31 | use MooseX::TypeLibrary |
32 | -declare => [qw( PositiveInt NegativeInt )]; |
33 | |
34 | # import builtin types |
35 | use MooseX::TypeLibrary::Moose 'Int'; |
36 | |
37 | # type definition |
38 | subtype PositiveInt, |
39 | as Int, |
40 | where { $_ > 0 }, |
41 | message { "Int is not larger than 0" }; |
42 | |
43 | subtype NegativeInt, |
44 | as Int, |
45 | where { $_ < 0 }, |
46 | message { "Int is not smaller than 0" }; |
47 | |
48 | # type coercion |
49 | coerce PositiveInt, |
50 | from Int, |
51 | via { 1 }; |
52 | |
53 | 1; |
54 | |
55 | # |
56 | # Usage |
57 | # |
58 | package Foo; |
59 | use Moose; |
60 | use MyLibrary qw( PositiveInt NegativeInt ); |
61 | |
62 | # use the exported constants as type names |
63 | has 'bar', |
64 | isa => PositiveInt, |
65 | is => 'rw'; |
66 | has 'baz', |
67 | isa => NegativeInt, |
68 | is => 'rw'; |
69 | |
70 | sub quux { |
71 | my ($self, $value); |
72 | |
73 | # test the value |
74 | print "positive\n" if is_PositiveInt($value); |
75 | print "negative\n" if is_NegativeInt($value); |
76 | |
77 | # coerce the value, NegativeInt doesn't have a coercion |
78 | # helper, since it didn't define any coercions. |
79 | $value = to_PositiveInt($value) or die "Cannot coerce"; |
80 | } |
81 | |
82 | 1; |
83 | |
84 | =head1 DESCRIPTION |
85 | |
86 | The types provided with L<Moose> are by design global. This package helps |
87 | you to organise and selectively import your own and the built-in types in |
88 | libraries. As a nice side effect, it catches typos at compile-time too. |
89 | |
90 | However, the main reason for this module is to provide an easy way to not |
91 | have conflicts with your type names, since the internal fully qualified |
92 | names of the types will be prefixed with the library's name. |
93 | |
94 | This module will also provide you with some helper functions to make it |
95 | easier to use Moose types in your code. |
96 | |
97 | =head1 TYPE HANDLER FUNCTIONS |
98 | |
99 | =head2 $type |
100 | |
101 | A constant with the name of your type. It contains the type's fully |
102 | qualified name. Takes no value, as all constants. |
103 | |
104 | =head2 is_$type |
105 | |
106 | This handler takes a value and tests if it is a valid value for this |
107 | C<$type>. It will return true or false. |
108 | |
109 | =head2 to_$type |
110 | |
111 | A handler that will take a value and coerce it into the C<$type>. It will |
112 | return a false value if the type could not be coerced. |
113 | |
114 | B<Important Note>: This handler will only be exported for types that can |
115 | do type coercion. This has the advantage that a coercion to a type that |
116 | cannot hasn't defined any coercions will lead to a compile-time error. |
117 | |
118 | =head1 LIBRARY DEFINITION |
119 | |
120 | A MooseX::TypeLibrary is just a normal Perl module. Unlike Moose |
121 | itself, it does not install C<use strict> and C<use warnings> in your |
122 | class by default, so this is up to you. |
123 | |
124 | The only thing a library is required to do is |
125 | |
126 | use MooseX::TypeLibrary -declare => \@types; |
127 | |
128 | with C<@types> being a list of types you wish to define in this library. |
129 | This line will install a proper base class in your package as well as the |
130 | full set of L<handlers|/"TYPE HANDLER FUNCTIONS"> for your declared |
131 | types. It will then hand control over to L<Moose::Util::TypeConstraints>' |
132 | C<import> method to export the functions you will need to declare your |
133 | types. |
134 | |
135 | If you want to use Moose' built-in types (e.g. for subtyping) you will |
136 | want to |
137 | |
138 | use MooseX::TypeLibrary::Moose @types; |
139 | |
140 | to import the helpers from the shipped L<MooseX::TypeLibrary::Moose> |
141 | library which can export all types that come with Moose. |
142 | |
143 | You will have to define coercions for your types or your library won't |
144 | export a L</to_$type> coercion helper for it. |
145 | |
146 | =head1 LIBRARY USAGE |
147 | |
148 | You can import the L<"type helpers"|/"TYPE HANDLER FUNCTIONS"> of a |
149 | library by C<use>ing it with a list of types to import as arguments. If |
150 | you want all of them, use the C<:all> tag. For example: |
151 | |
152 | use MyLibrary ':all'; |
153 | use MyOtherLibrary qw( TypeA TypeB ); |
154 | |
155 | MooseX::TypeLibrary comes with a library of Moose' built-in types called |
156 | L<MooseX::TypeLibrary::Moose>. |
157 | |
158 | =head1 METHODS |
159 | |
160 | =head2 import |
161 | |
162 | =cut |
163 | |
164 | sub import { |
165 | my ($class, %args) = @_; |
166 | my $callee = caller; |
167 | |
168 | # inject base class into new library |
169 | { no strict 'refs'; |
170 | unshift @{ $callee . '::ISA' }, 'MooseX::TypeLibrary::Base'; |
171 | } |
172 | |
173 | # generate predeclared type helpers |
174 | if (my @declare = @{ $args{ -declare } || [] }) { |
175 | for my $type (@declare) { |
176 | $callee->add_type($type); |
177 | $callee->export_type_into( |
178 | $callee, $type, |
179 | sprintf($UndefMsg, $type, $callee), |
180 | -full => 1, |
181 | ); |
182 | } |
183 | } |
184 | |
185 | # run type constraints import |
186 | return uplevel 1, |
187 | Moose::Util::TypeConstraints->can('import'), |
188 | 'Moose::Util::TypeConstraints'; |
189 | } |
190 | |
191 | =head2 type_export_generator |
192 | |
193 | =cut |
194 | |
195 | sub type_export_generator { |
196 | my ($class, $type, $full) = @_; |
197 | return sub { $full }; |
198 | } |
199 | |
200 | =head2 coercion_export_generator |
201 | |
202 | =cut |
203 | |
204 | sub coercion_export_generator { |
205 | my ($class, $type, $full, $undef_msg) = @_; |
206 | return sub { |
207 | my ($value) = @_; |
208 | |
209 | # we need a type object |
210 | my $tobj = find_type_constraint($full) or croak $undef_msg; |
211 | my $return = $tobj->coerce($value); |
212 | |
213 | # non-successful coercion returns false |
214 | return unless $tobj->check($return); |
215 | |
216 | return $return; |
217 | } |
218 | } |
219 | |
220 | =head2 check_export_generator |
221 | |
222 | =cut |
223 | |
224 | sub check_export_generator { |
225 | my ($class, $type, $full, $undef_msg) = @_; |
226 | return sub { |
227 | my ($value) = @_; |
228 | |
229 | # we need a type object |
230 | my $tobj = find_type_constraint($full) or croak $undef_msg; |
231 | |
232 | return $tobj->check($value); |
233 | } |
234 | } |
235 | |
236 | =head1 SEE ALSO |
237 | |
238 | L<Moose>, L<Moose::Util::TypeConstraints>, L<MooseX::TypeLibrary::Moose> |
239 | |
240 | =head1 AUTHOR AND COPYRIGHT |
241 | |
242 | Robert 'phaylon' Sedlacek C<E<lt>rs@474.atE<gt>>, with many thanks to |
243 | the C<#moose> cabal on C<irc.perl.org>. |
244 | |
245 | =head1 LICENSE |
246 | |
247 | This program is free software; you can redistribute it and/or modify |
248 | it under the same terms as perl itself. |
249 | |
250 | =cut |
251 | |
252 | 1; |