1Specio::Declare(3) User Contributed Perl Documentation Specio::Declare(3)
2
6 Specio::Declare - Specio declaration subroutines
7
9 version 0.42
10
12 package MyApp::Type::Library;
13 use parent 'Specio::Exporter';
15 use Specio::Declare;
17 use Specio::Library::Builtins;
18 declare(
20 'Foo',
21 parent => t('Str'),
22 where => sub { $_[0] =~ /foo/i },
23 );
24 declare(
26 'ArrayRefOfInt',
27 parent => t( 'ArrayRef', of => t('Int') ),
28 );
29 my $even = anon(
31 parent => t('Int'),
32 inline => sub {
33 my $type = shift;
34 my $value_var = shift;
35 return $value_var . ' % 2 == 0';
37 },
38 );
39 coerce(
41 t('ArrayRef'),
42 from => t('Foo'),
43 using => sub { [ $_[0] ] },
44 );
45 coerce(
47 $even,
48 from => t('Int'),
49 using => sub { $_[0] % 2 ? $_[0] + 1 : $_[0] },
50 );
51 # Specio name is DateTime
53 any_isa_type('DateTime');
54 # Specio name is DateTimeObject
56 object_isa_type( 'DateTimeObject', class => 'DateTime' );
57 any_can_type(
59 'Duck',
60 methods => [ 'duck_walk', 'quack' ],
61 );
62 object_can_type(
64 'DuckObject',
65 methods => [ 'duck_walk', 'quack' ],
66 );
67 enum(
69 'Colors',
70 values => [qw( blue green red )],
71 );
72 intersection(
74 'HashRefAndArrayRef',
75 of => [ t('HashRef'), t('ArrayRef') ],
76 );
77 union(
79 'IntOrArrayRef',
80 of => [ t('Int'), t('ArrayRef') ],
81 );
82
84 This package exports a set of type declaration helpers. Importing this
85 package also causes it to create a "t" subroutine the caller.
86
88 This module exports the following subroutines.
89 t('name')
91 This subroutine lets you access any types you have declared so far, as
92 well as any types you imported from another type library.
93 If you pass an unknown name, it throws an exception.
95 declare(...)
97 This subroutine declares a named type. The first argument is the type
98 name, followed by a set of key/value parameters:
99 · parent => $type
101 The parent should be another type object. Specifically, it can be
103 anything which does the Specio::Constraint::Role::Interface role.
104 The parent can be a named or anonymous type.
105 · where => sub { ... }
107 This is a subroutine which defines the type constraint. It will be
109 passed a single argument, the value to check, and it should return
110 true or false to indicate whether or not the value is valid for the
111 type.
112 This parameter is mutually exclusive with the "inline" parameter.
114 · inline => sub { ... }
116 This is a subroutine that is called to generate inline code to
118 validate the type. Inlining can be much faster than simply
119 providing a subroutine with the "where" parameter, but is often
120 more complicated to get right.
121 The inline generator is called as a method on the type with one
123 argument. This argument is a string containing the variable name to
124 use in the generated code. Typically this is something like '$_[0]'
125 or '$value'.
126 The inline generator subroutine should return a string of code
128 representing a single term, and it should not be terminated with a
129 semicolon. This allows the inlined code to be safely included in an
130 "if" statement, for example. You can use "do { }" blocks and
131 ternaries to get everything into one term. Do not assign to the
132 variable you are testing. This single term should evaluate to true
133 or false.
134 The inline generator is expected to include code to implement both
136 the current type and all its parents. Typically, the easiest way to
137 do this is to write a subroutine something like this:
138 sub {
140 my $self = shift;
141 my $var = shift;
142 return $_[0]->parent->inline_check( $_[1] )
144 . ' and more checking code goes here';
145 }
146 This parameter is mutually exclusive with the "where" parameter.
148 · message_generator => sub { ... }
150 A subroutine to generate an error message when the type check
152 fails. The default message says something like "Validation failed
153 for type named Int declared in package Specio::Library::Builtins
154 (.../Specio/blib/lib/Specio/Library/Builtins.pm) at line 147 in sub
155 named (eval) with value 1.1".
156 You can override this to provide something more specific about the
158 way the type failed.
159 The subroutine you provide will be called as a method on the type
161 with two arguments. The first is the description of the type (the
162 bit in the message above that starts with "type named Int ..." and
163 ends with "... in sub named (eval)". This description says what the
164 thing is and where it was defined.
165 The second argument is the value that failed the type check, after
167 any coercions that might have been applied.
168 anon(...)
170 This subroutine declares an anonymous type. It is identical to
171 "declare" except that it expects a list of key/value parameters without
172 a type name as the first parameter.
173 coerce(...)
175 This declares a coercion from one type to another. The first argument
176 should be an object which does the Specio::Constraint::Role::Interface
177 role. This can be either a named or anonymous type. This type is the
178 type that the coercion is to.
179 The remaining arguments are key/value parameters:
181 · from => $type
183 This must be an object which does the
185 Specio::Constraint::Role::Interface role. This is type that we are
186 coercing from. Again, this can be either a named or anonymous type.
187 · using => sub { ... }
189 This is a subroutine which defines the type coercion. It will be
191 passed a single argument, the value to coerce. It should return a
192 new value of the type this coercion is to.
193 This parameter is mutually exclusive with the "inline" parameter.
195 · inline => sub { ... }
197 This is a subroutine that is called to generate inline code to
199 perform the coercion.
200 The inline generator is called as a method on the type with one
202 argument. This argument is a string containing the variable name to
203 use in the generated code. Typically this is something like '$_[0]'
204 or '$value'.
205 The inline generator subroutine should return a string of code
207 representing a single term, and it should not be terminated with a
208 semicolon. This allows the inlined code to be safely included in an
209 "if" statement, for example. You can use "do { }" blocks and
210 ternaries to get everything into one term. This single term should
211 evaluate to the new value.
212
214 This module also exports some helper subs for declaring certain kinds
215 of types:
216 any_isa_type, object_isa_type
218 The "any_isa_type" helper creates a type which accepts a class name or
219 object of the given class. The "object_isa_type" helper creates a type
220 which only accepts an object of the given class.
221 These subroutines take a type name as the first argument. The remaining
223 arguments are key/value pairs. Currently this is just the "class" key,
224 which should be a class name. This is the class that the type requires.
225 The type name argument can be omitted to create an anonymous type.
227 You can also pass just a single argument, in which case that will be
229 used as both the type's name and the class for the constraint to check.
230 any_does_type, object_does_type
232 The "any_does_type" helper creates a type which accepts a class name or
233 object which does the given role. The "object_does_type" helper creates
234 a type which only accepts an object which does the given role.
235 These subroutines take a type name as the first argument. The remaining
237 arguments are key/value pairs. Currently this is just the "role" key,
238 which should be a role name. This is the class that the type requires.
239 This should just work (I hope) with roles created by Moose, Mouse, and
241 Moo (using Role::Tiny).
242 The type name argument can be omitted to create an anonymous type.
244 You can also pass just a single argument, in which case that will be
246 used as both the type's name and the role for the constraint to check.
247 any_can_type, object_can_type
249 The "any_can_type" helper creates a type which accepts a class name or
250 object with the given methods. The "object_can_type" helper creates a
251 type which only accepts an object with the given methods.
252 These subroutines take a type name as the first argument. The remaining
254 arguments are key/value pairs. Currently this is just the "methods"
255 key, which can be either a string or array reference of strings. These
256 strings are the required methods for the type.
257 The type name argument can be omitted to create an anonymous type.
259 enum
261 This creates a type which accepts a string matching a given list of
262 acceptable values.
263 The first argument is the type name. The remaining arguments are
265 key/value pairs. Currently this is just the "values" key. This should
266 an array reference of acceptable string values.
267 The type name argument can be omitted to create an anonymous type.
269 intersection
271 This creates a type which is the intersection of two or more other
272 types. A union only accepts values which match all of its underlying
273 types.
274 The first argument is the type name. The remaining arguments are
276 key/value pairs. Currently this is just the "of" key. This should an
277 array reference of types.
278 The type name argument can be omitted to create an anonymous type.
280 union
282 This creates a type which is the union of two or more other types. A
283 union accepts any of its underlying types.
284 The first argument is the type name. The remaining arguments are
286 key/value pairs. Currently this is just the "of" key. This should an
287 array reference of types.
288 The type name argument can be omitted to create an anonymous type.
290
292 You can create a parameterized type by calling "t" with additional
293 parameters, like this:
294 my $arrayref_of_int = t( 'ArrayRef', of => t('Int') );
296 my $arrayref_of_hashref_of_int = t(
298 'ArrayRef',
299 of => t(
300 'HashRef',
301 of => t('Int'),
302 ),
303 );
304 The "t" subroutine assumes that if it receives more than one argument,
306 it should look up the named type and call "$type->parameterize(...)"
307 with the additional arguments.
308 If the named type cannot be parameterized, it throws an error.
310 You can also call "$type->parameterize" directly if needed. See
312 Specio::Constraint::Parameterizable for details.
313
315 Bugs may be submitted at
316 <https://github.com/houseabsolute/Specio/issues>.
317 I am also usually active on IRC as 'autarch' on "irc://irc.perl.org".
319
321 The source code repository for Specio can be found at
322 <https://github.com/houseabsolute/Specio>.
323
325 Dave Rolsky <autarch@urth.org>
326
328 This software is Copyright (c) 2012 - 2017 by Dave Rolsky.
329 This is free software, licensed under:
331 The Artistic License 2.0 (GPL Compatible)
333 The full text of the license can be found in the LICENSE file included
335 with this distribution.
336perl v5.28.0 2017-11-04 Specio::Declare(3)