Open Source Projects


Prelude is a library of Haskell-style operations written in Ruby with the goal of enabling higher-order functions and monads.

The general idea is that functional programming provides many benefits, which are not directly available in Ruby out of the box. This library will, hopefully, provide an infrastructure for the use of most Haskell’s functional idioms. It will also facilitate a more or less direct port to Ruby of algorithms and data structures already developed by functional community.

The development is discontinued due to the advancement of Scala which has everything a functional programmer has ever wanted.

Project home was at, but the site is now defunct.


The latest available library version can be downloaded from and here is the documentation.


Prelude library is released under the Lesser GPL license.