# Test2::Util::HashBase - phpMan

## 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;    # 'MyFoo'
        my $bar = $one->bar;    # 'MyBar'
        my $baz = $one->baz;    # Defaulted 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

        # 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');

        # '<bat' means no setter defined at all
        # '+boo' means no setter or reader, just the BOO constant

        $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.

  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.

    See <http://dev.perl.org/licenses/>