Manpages - Test2_Util_HashBase.3perl
Table of Contents
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 <bat >ban +boo/; # Chance to initialize defaults sub init { my $self = shift; # No other args $self->{+FOO} ||= “foo”; $self->{+BAR} ||= “bar”; $self->{+BAZ} ||= “baz”; $self->{+BAT} ||= “bat”; $self->{+BAN} ||= “ban”; $self->{+BOO}
| = “boo”; } sub print { print join “, ” => map { $self->{$_} } FOO, |
BAR, BAZ, BAT, BAN, BOO; }
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/bub/; sub init { my $self = shift; # We get the constants from the base class for free. $self->{+FOO} ||= SubFoo; $self->{+BUB} ||= bub; $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]); # Readers! my $foo = $one->foo;
to: baz my $bat = $one->bat; # Defaulted to: bat # >ban means setter only, no reader # +boo means no setter or reader, just the BOO constant
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); # <bat means no setter defined at all
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
$selfwith its indexes already set from the constructor. Note: Test2::Util::HashBase checks for an init using$class->can(init)during construction. It DOES NOT callcan()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 aninit()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
foofield. - set_foo()
- Setter, used to set the value of the
foofield. - 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.
NO SETTER
use Test2::Util::HashBase qw/<foo/;
Only gives you a reader, no set_foo method is defined at all.
NO READER
use Test2::Util::HashBase qw/>foo/;
Only gives you a write (set_foo), no foo method is defined at all.
CONSTANT ONLY
use Test2::Util::HashBase qw/+foo/;
This does not create any methods for you, it just adds the FOO
constant.
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@cpan.org>
AUTHORS
- Chad Granum <exodist@cpan.org>
COPYRIGHT
Copyright 2017 Chad Granum <exodist@cpan.org>.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.