Data::Enum - immutable enumeration classes
version v0.2.7
use Data::Enum; my $color = Data::Enum->new( qw[ red yellow blue green ] ); my $red = $color->new("red"); $red->is_red; # "1" $red->is_yellow; # "" (false) $red->is_blue; # "" (false) $red->is_green; # "" (false) say $red; # outputs "red" $red eq $color->new("red"); # true $red eq "red"; # true
This module will create enumerated constant classes with the following properties:
Any two classes with the same elements are equivalent.
The following two classes are the same:
my $one = Data::Enum->new( qw[ foo bar baz ] ); my $two = Data::Enum->new( qw[ foo bar baz ] );
All class instances are singletons.
my $one = Data::Enum->new( qw[ foo bar baz ] ); my $a = $one->new("foo") my $b = $one->new("foo"); refaddr($a) == refaddr($b); # they are the same thing
Methods for checking values are fast.
$a->is_foo; # constant time $a eq $b; # compares refaddr
Values are immutable (read-only).
This is done by creating a unique internal class name based on the possible values. Each value is actually a subclass of that class, with the appropriate is_ method returning a constant.
is_
my $class = Data::Enum->new( @values );
This creates a new anonymous class. Values can be instantiated with a constructor:
my $instance = $class->new( $value );
Calling the constructor with an invalid value will throw an exception.
Each instance will have an is_ method for each value.
Each instance stringifies to its value.
my @values = $class->values;
Returns a list of valid values, stringified and sorted with duplicates removed.
This was added in v0.2.0.
my @predicates = $class->predicates;
Returns a list of predicate methods for each value.
A hash of predicates to values is roughly
use List::Util 1.56 'mesh'; my %handlers = mesh [ $class->values ], [ $class->predicates ];
This was added in v0.2.1.
This method adds support for match::simple.
The overheard of creating a new class instance and resolving methods may actually take more time than comparing simple strings. When using this in production code, you may want to benchmark performance.
This module requires Perl v5.10 or later.
Future releases may only support Perl versions released in the last ten years.
Class::Enum
Object::Enum
MooX::Enumeration
MooseX::Enumeration
Type::Tiny::Enum
The development version is on github at https://github.com/robrwo/perl-Data-Enum and may be cloned from git://github.com/robrwo/perl-Data-Enum.git
Please report any bugs or feature requests on the bugtracker website https://github.com/robrwo/perl-Data-Enum/issues
When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.
Robert Rothenberg <rrwo@cpan.org>
This software is Copyright (c) 2021-2023 by Robert Rothenberg.
This is free software, licensed under:
The Artistic License 2.0 (GPL Compatible)
To install Data::Enum, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Data::Enum
CPAN shell
perl -MCPAN -e shell install Data::Enum
For more information on module installation, please visit the detailed CPAN module installation guide.