Free software programmed in Haskell

thumb|xmonad's Xinerama support: tiling on three screens simultaneously. thumb|xmonad in tiling window manager|tiling mode xmonad is a dynamic window manager (tiling) for the X Window System, noted for being written in the functional programming language Haskell.

Pandoc is a free-software document converter, widely used as a writing tool (especially by scholars) and as a basis for publishing workflows. It was created by John MacFarlane, a philosophy professor at the University of California, Berkeley.

dependently typed, purely functional programming language and proof assistant

Darcs is a distributed version control system created by David Roundy. Key features include the ability to choose which changes to accept from other repositories, interaction with either other local (on-disk) repositories or remote repositories via SSH, HTTP, or email, and an unusually interactive interface. The developers also emphasize the use of advanced software tools for verifying correctness: the expressive type system of the functional programming language Haskell enforces some properties, and randomized testing via QuickCheck verifies many others. The name is a recursive acronym for Da

purely functional programming language

privacy preserving communication app

Haskell implementation of Perl 6