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=pod

=head1 NAME

Class::Enumeration - Abstract parent class of enum classes

=head1 SYNOPSIS

  use strict;
  use warnings;

  package TurnstileState;

  use parent 'Class::Enumeration';

  # Define list of enum objects
  my @values;
  sub values { no critic ( ProhibitBuiltinHomonyms )
    my $ordinal = 0;
    @values = map { __PACKAGE__->_new( $ordinal++, $_ ) } qw( Locked Unlocked )
      unless @values;
    @values
  }

  1

=head1 CAVEAT

This class is abstract. It defines and partially implements the API
of enum classes. It should not be used directly. You should use the
L<Class::Enumeration::Builder> module instead.

=head1 DESCRIPTION

An enum class is a list of enum objects. Each enum object is immutable and
has a C<name> and an C<ordinal> attribute.

Each enum class has a C<name()> getter method (an object method), that
returns the C<name> of the enum object, exactly as defined.

Each enum class has an C<ordinal()> getter method (an object method),
that returns the C<ordinal> number of the enum object. It defaults to the
position in its definition, where the initial object is assigned an ordinal
number of zero.

Each enum class has a C<names()> class method, that returns the list of
names of the enum objects in the order they were defined.

Each enum class has a C<values()> class method, that returns the list of the
enum objects sorted according to their ordinal number (lowest to highest). This
method is abstract and gets implemented by the C<Class::Enumeration::Builder>
module.

Each enum class has a C<value_of( $name )> factory method (a class method),
that returns the enum object with the specified name.

Each enum class inherits stringification C<'""'> from its C<Class::Enumeration>
parent class. By default the string representation of an enum object returns
its C<name>. If you want to override this behaviour, you have to provide an
C<to_string()> implementation in your enum class.

The parent class C<Class::Enumeration> overloads the operators C<'=='>,
and C<'!='> too. Magic auto-generation of overload implementations for
other operators is turned off. An enum class can add its own overload
implementations.

=head1 SEE ALSO

=over 2

=item *

L<Class::Enum>

=item *

L<Class::Type::Enum>

=item *