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Test2::Util::HashBase(User Contributed Perl DocumentatTest2::Util::HashBase(3)
NAME
       Test2::Util::HashBase - Build hash based classes.
SYNOPSIS
       A class:
           package My::Class;
           use strict;
           use warnings;
           # Generate 3 accessors
           use Test2::Util::HashBase qw/foo -bar ^baz/;
           # Chance to initialize defaults
           sub init {
               my $self = shift;    # No other args
               $self->{+FOO} ||= "foo";
               $self->{+BAR} ||= "bar";
               $self->{+BAZ} ||= "baz";
           }
           sub print {
               print join ", " => map { $self->{$_} } FOO, BAR, BAZ;
           }
       Subclass it
           package My::Subclass;
           use strict;
           use warnings;
           # Note, you should subclass before loading HashBase.
           use base 'My::Class';
           use Test2::Util::HashBase qw/bat/;
           sub init {
               my $self = shift;
               # We get the constants from the base class for free.
               $self->{+FOO} ||= 'SubFoo';
               $self->{+BAT} ||= 'bat';
               $self->SUPER::init();
           }
       use it:
           package main;
           use strict;
           use warnings;
           use My::Class;
           # These are all functionally identical
           my $one   = My::Class->new(foo => 'MyFoo', bar => 'MyBar');
           my $two   = My::Class->new({foo => 'MyFoo', bar => 'MyBar'});
           my $three = My::Class->new(['MyFoo', 'MyBar']);
           # Accessors!
           my $foo = $one->foo;    # 'MyFoo'
           my $bar = $one->bar;    # 'MyBar'
           my $baz = $one->baz;    # Defaulted to: 'baz'
           # Setters!
           $one->set_foo('A Foo');
           #'-bar' means read-only, so the setter will throw an exception (but is defined).
           $one->set_bar('A bar');
           # '^baz' means deprecated setter, this will warn about the setter being
           # deprecated.
           $one->set_baz('A Baz');
           $one->{+FOO} = 'xxx';
DESCRIPTION
       This package is used to generate classes based on hashrefs. Using this
       class will give you a "new()" method, as well as generating accessors
       you request.  Generated accessors will be getters, "set_ACCESSOR"
       setters will also be generated for you. You also get constants for each
       accessor (all caps) which return the key into the hash for that
       accessor. Single inheritance is also supported.
THIS IS A BUNDLED COPY OF HASHBASE
       This is a bundled copy of Object::HashBase. This file was generated
       using the "/home/exodist/perl5/perlbrew/perls/main/bin/hashbase_inc.pl"
       script.
METHODS
   PROVIDED BY HASH BASE
       $it = $class->new(%PAIRS)
       $it = $class->new(\%PAIRS)
       $it = $class->new(\@ORDERED_VALUES)
           Create a new instance.
           HashBase will not export "new()" if there is already a "new()"
           method in your packages inheritance chain.
           If you do not want this method you can define your own you just
           have to declare it before loading Test2::Util::HashBase.
               package My::Package;
               # predeclare new() so that HashBase does not give us one.
               sub new;
               use Test2::Util::HashBase qw/foo bar baz/;
               # Now we define our own new method.
               sub new { ... }
           This makes it so that HashBase sees that you have your own "new()"
           method.  Alternatively you can define the method before loading
           HashBase instead of just declaring it, but that scatters your use
           statements.
           The most common way to create an object is to pass in key/value
           pairs where each key is an attribute and each value is what you
           want assigned to that attribute. No checking is done to verify the
           attributes or values are valid, you may do that in "init()" if
           desired.
           If you would like, you can pass in a hashref instead of pairs. When
           you do so the hashref will be copied, and the copy will be returned
           blessed as an object.  There is no way to ask HashBase to bless a
           specific hashref.
           In some cases an object may only have 1 or 2 attributes, in which
           case a hashref may be too verbose for your liking. In these cases
           you can pass in an arrayref with only values. The values will be
           assigned to attributes in the order the attributes were listed.
           When there is inheritance involved the attributes from parent
           classes will come before subclasses.
   HOOKS
       $self->init()
           This gives you the chance to set some default values to your
           fields. The only argument is $self with its indexes already set
           from the constructor.
           Note: Test2::Util::HashBase checks for an init using
           "$class->can('init')" during construction. It DOES NOT call "can()"
           on the created object. Also note that the result of the check is
           cached, it is only ever checked once, the first time an instance of
           your class is created. This means that adding an "init()" method
           AFTER the first construction will result in it being ignored.
ACCESSORS
   READ/WRITE
       To generate accessors you list them when using the module:
           use Test2::Util::HashBase qw/foo/;
       This will generate the following subs in your namespace:
       foo()
           Getter, used to get the value of the "foo" field.
       set_foo()
           Setter, used to set the value of the "foo" field.
       FOO()
           Constant, returns the field "foo"'s key into the class hashref.
           Subclasses will also get this function as a constant, not simply a
           method, that means it is copied into the subclass namespace.
           The main reason for using these constants is to help avoid spelling
           mistakes and similar typos. It will not help you if you forget to
           prefix the '+' though.
   READ ONLY
           use Test2::Util::HashBase qw/-foo/;
       set_foo()
           Throws an exception telling you the attribute is read-only. This is
           exported to override any active setters for the attribute in a
           parent class.
   DEPRECATED SETTER
           use Test2::Util::HashBase qw/^foo/;
       set_foo()
           This will set the value, but it will also warn you that the method
           is deprecated.
SUBCLASSING
       You can subclass an existing HashBase class.
           use base 'Another::HashBase::Class';
           use Test2::Util::HashBase qw/foo bar baz/;
       The base class is added to @ISA for you, and all constants from base
       classes are added to subclasses automatically.
GETTING A LIST OF ATTRIBUTES FOR A CLASS
       Test2::Util::HashBase provides a function for retrieving a list of
       attributes for an Test2::Util::HashBase class.
       @list = Test2::Util::HashBase::attr_list($class)
       @list = $class->Test2::Util::HashBase::attr_list()
           Either form above will work. This will return a list of attributes
           defined on the object. This list is returned in the attribute
           definition order, parent class attributes are listed before
           subclass attributes. Duplicate attributes will be removed before
           the list is returned.
           Note: This list is used in the "$class->new(\@ARRAY)" constructor
           to determine the attribute to which each value will be paired.
SOURCE
       The source code repository for HashBase can be found at
       http://github.com/Test-More/HashBase/.
MAINTAINERS
       Chad Granum <exodist AT cpan.org>
AUTHORS
       Chad Granum <exodist AT cpan.org>
COPYRIGHT
       Copyright 2019 Chad Granum <exodist AT cpan.org>.
       This program is free software; you can redistribute it and/or modify it
       under the same terms as Perl itself.
       See http://dev.perl.org/licenses/
perl v5.16.3                      2019-09-06          Test2::Util::HashBase(3)