1Test2::Harness::Util::HUassehrBaCsoen(t3r)ibuted Perl DoTceusmte2n:t:aHtaironness::Util::HashBase(3)
2
6 Test2::Harness::Util::HashBase - Build hash based classes.
7
9 A class:
10 package My::Class;
12 use strict;
13 use warnings;
14 # Generate 3 accessors
16 use Test2::Harness::Util::HashBase qw/foo -bar ^baz/;
17 # Chance to initialize defaults
19 sub init {
20 my $self = shift; # No other args
21 $self->{+FOO} ||= "foo";
22 $self->{+BAR} ||= "bar";
23 $self->{+BAZ} ||= "baz";
24 }
25 sub print {
27 print join ", " => map { $self->{$_} } FOO, BAR, BAZ;
28 }
29 Subclass it
31 package My::Subclass;
33 use strict;
34 use warnings;
35 # Note, you should subclass before loading HashBase.
37 use base 'My::Class';
38 use Test2::Harness::Util::HashBase qw/bat/;
39 sub init {
41 my $self = shift;
42 # We get the constants from the base class for free.
44 $self->{+FOO} ||= 'SubFoo';
45 $self->{+BAT} ||= 'bat';
46 $self->SUPER::init();
48 }
49 use it:
51 package main;
53 use strict;
54 use warnings;
55 use My::Class;
56 # These are all functionally identical
58 my $one = My::Class->new(foo => 'MyFoo', bar => 'MyBar');
59 my $two = My::Class->new({foo => 'MyFoo', bar => 'MyBar'});
60 my $three = My::Class->new(['MyFoo', 'MyBar']);
61 # Accessors!
63 my $foo = $one->foo; # 'MyFoo'
64 my $bar = $one->bar; # 'MyBar'
65 my $baz = $one->baz; # Defaulted to: 'baz'
66 # Setters!
68 $one->set_foo('A Foo');
69 #'-bar' means read-only, so the setter will throw an exception (but is defined).
71 $one->set_bar('A bar');
72 # '^baz' means deprecated setter, this will warn about the setter being
74 # deprecated.
75 $one->set_baz('A Baz');
76 $one->{+FOO} = 'xxx';
78
80 This package is used to generate classes based on hashrefs. Using this
81 class will give you a "new()" method, as well as generating accessors
82 you request. Generated accessors will be getters, "set_ACCESSOR"
83 setters will also be generated for you. You also get constants for each
84 accessor (all caps) which return the key into the hash for that
85 accessor. Single inheritance is also supported.
86
88 This is a bundled copy of Object::HashBase. This file was generated
89 using the "/home/exodist/perl5/perlbrew/perls/main/bin/hashbase_inc.pl"
90 script.
91
93 PROVIDED BY HASH BASE
94 $it = $class->new(%PAIRS)
95 $it = $class->new(\%PAIRS)
96 $it = $class->new(\@ORDERED_VALUES)
97 Create a new instance.
98 HashBase will not export "new()" if there is already a "new()"
100 method in your packages inheritance chain.
101 If you do not want this method you can define your own you just
103 have to declare it before loading Test2::Harness::Util::HashBase.
104 package My::Package;
106 # predeclare new() so that HashBase does not give us one.
108 sub new;
109 use Test2::Harness::Util::HashBase qw/foo bar baz/;
111 # Now we define our own new method.
113 sub new { ... }
114 This makes it so that HashBase sees that you have your own "new()"
116 method. Alternatively you can define the method before loading
117 HashBase instead of just declaring it, but that scatters your use
118 statements.
119 The most common way to create an object is to pass in key/value
121 pairs where each key is an attribute and each value is what you
122 want assigned to that attribute. No checking is done to verify the
123 attributes or values are valid, you may do that in "init()" if
124 desired.
125 If you would like, you can pass in a hashref instead of pairs. When
127 you do so the hashref will be copied, and the copy will be returned
128 blessed as an object. There is no way to ask HashBase to bless a
129 specific hashref.
130 In some cases an object may only have 1 or 2 attributes, in which
132 case a hashref may be too verbose for your liking. In these cases
133 you can pass in an arrayref with only values. The values will be
134 assigned to attributes in the order the attributes were listed.
135 When there is inheritance involved the attributes from parent
136 classes will come before subclasses.
137 HOOKS
139 $self->init()
140 This gives you the chance to set some default values to your
141 fields. The only argument is $self with its indexes already set
142 from the constructor.
143 Note: Test2::Harness::Util::HashBase checks for an init using
145 "$class->can('init')" during construction. It DOES NOT call "can()"
146 on the created object. Also note that the result of the check is
147 cached, it is only ever checked once, the first time an instance of
148 your class is created. This means that adding an "init()" method
149 AFTER the first construction will result in it being ignored.
150
152 READ/WRITE
153 To generate accessors you list them when using the module:
154 use Test2::Harness::Util::HashBase qw/foo/;
156 This will generate the following subs in your namespace:
158 foo()
160 Getter, used to get the value of the "foo" field.
161 set_foo()
163 Setter, used to set the value of the "foo" field.
164 FOO()
166 Constant, returns the field "foo"'s key into the class hashref.
167 Subclasses will also get this function as a constant, not simply a
168 method, that means it is copied into the subclass namespace.
169 The main reason for using these constants is to help avoid spelling
171 mistakes and similar typos. It will not help you if you forget to
172 prefix the '+' though.
173 READ ONLY
175 use Test2::Harness::Util::HashBase qw/-foo/;
176 set_foo()
178 Throws an exception telling you the attribute is read-only. This is
179 exported to override any active setters for the attribute in a
180 parent class.
181 DEPRECATED SETTER
183 use Test2::Harness::Util::HashBase qw/^foo/;
184 set_foo()
186 This will set the value, but it will also warn you that the method
187 is deprecated.
188
190 You can subclass an existing HashBase class.
191 use base 'Another::HashBase::Class';
193 use Test2::Harness::Util::HashBase qw/foo bar baz/;
194 The base class is added to @ISA for you, and all constants from base
196 classes are added to subclasses automatically.
197
199 Test2::Harness::Util::HashBase provides a function for retrieving a
200 list of attributes for an Test2::Harness::Util::HashBase class.
201 @list = Test2::Harness::Util::HashBase::attr_list($class)
203 @list = $class->Test2::Harness::Util::HashBase::attr_list()
204 Either form above will work. This will return a list of attributes
205 defined on the object. This list is returned in the attribute
206 definition order, parent class attributes are listed before
207 subclass attributes. Duplicate attributes will be removed before
208 the list is returned.
209 Note: This list is used in the "$class->new(\@ARRAY)" constructor
211 to determine the attribute to which each value will be paired.
212
214 The source code repository for HashBase can be found at
215 http://github.com/Test-More/HashBase/.
216
218 Chad Granum <exodist@cpan.org>
219
221 Chad Granum <exodist@cpan.org>
222
224 Copyright 2019 Chad Granum <exodist@cpan.org>.
225 This program is free software; you can redistribute it and/or modify it
227 under the same terms as Perl itself.
228 See http://dev.perl.org/licenses/
230perl v5.30.1 2020-01-30 Test2::Harness::Util::HashBase(3)