Class::Constant allows you declaratively created so-called "constant
classes". These are very much like enumerated types (as close as a
typeless language like Perl can get, at least).

The classes generated by this module are modeled closely after Java's
"typesafe enumeration" pattern, but with some added spice to make them
more useful to Perl programs.

WWW: https://metacpan.org/release/Class-Constant