Funkr brings some common functional programming constructs to ruby.

In particular, it offers a simple mechanism to create Algebraic Data
Types and do pattern matching on them. For an exemple implementation,
see provided classes.

It also provide modules for common categories (Monoid, Monad,
Functor, Applicative ...), and extends common types to support
categories they belongs to (Array, Hash ...). Categories can also be
used with custom types,  see provided classes.

To get started, we recommand you to read the tests, and get feets wet
with provided Algebraic Data Types (like Maybe).

Funkr is heavily used by its authors in production at
http://www.atikteam.com/en to ensure better code reliability.