A Compiler Toolkit in Haskell - A set of modules for creating compilers in Haskell. [Open Source, GPL]
APSET - A project to provide better run-time profiling information for GpH.
CGI Library - Helps you build web applications in Haskell.
DrIFT - A Haskell preprocessor for generating instances of classes.
FranTk - A high level library for building GUIs in Haskell. It provides good support for developing complex dynamic systems, and is built on top of Tcl/Tk. [Open Source, BSD-like]
Fudgets - A Graphical User Interface toolkit for Haskell and the X-Windows system. [Free for non-commercial use]
Glasgow Parallel Haskell (GpH) - A Haskell extension for parallel programming built on top of the Glasgow Haskell compiler (GHC). Parallelism is identified using annotations (generally evaluation strategies), that are defined using only two extra primitives: par and seq.
Green Card - A foreign function interface preprocessor, simplifying the task of interfacing Haskell programs to external libraries.
Haggis - A multi-threaded, concurrent user interface framework for Haskell (X-Windows).
Happy - A parser generator for Haskell.
Haskell (literate style) mode for Vim - Syntax highlighting for literate Haskell scripts for the editor Vim by John Williams.
Haskell -The Craft of Functional Programming - Home page for the introductory textbook on programming in Haskell, written by Simon Thompson.
Haskell Mode for Emacs - An Emacs mode currently supporting font locking, declaration scanning, documentation, indentation, hugs interaction.
Haskell mode for Nedit - An Nedit mode by Koen Claessen that implements syntax highlighting and macros for Haskell comments.
Haskell mode for Vim - Syntax highlighting mode for Vim by John Williams.
Haskell Reference at Zvon - A thoroughly indexed reference to Haskell syntax and libraries with many examples.
Haskell Tutorial - A tutorial on Haskell from Walla Walla College
Haskell++ - an object oriented extension of Haskell, using a preprocessor.
HaskellDirect - An (Independent definition language) IDL compiler for Haskell. Can be used to interface foreign language libraries and call COM methods from Haskell.
HaSQL Project - An ODBC interface to Haskell implemented using Green Card.
Hello, World program - What Hello World in Haskell looks like.
HGL Graphics Library - A portable graphics library for both X11 and Win32. [Open Source, BSD-like]
HOpenGL - An OpenGL/GLUT binding for Haskell. [Open Source, LGPL]
Hugs - An interpreter for Haskell which runs on almost any platform. Primarily used for teaching.
Hugs mode for Emacs - Provides fontification and cooperation with Hugs -- by Chris Van Humbeeck.
Jaskell Project Home Page - A Java Bytecodes generator for Haskell.
Java VM Bridge - A bridge to the Java virtual machine via JNI for Haskell. [Open Source, LGPL]
JCreator for Haskell - An extension to JCreator, adding Hugs to JCreator as a tool and providing syntax-highlighting for Haskell.
Monads for the Working Haskell Programmer - This short tutorial introduces monads to Haskell programmers.
MySQL-HS - An interface to the database MySQL for the programming language Haskell. [Open Source, LGPL]
nhc98 from York - A Haskell 98 compiler.
O'Haskell - Object Haskell: Haskell conservatively extended with subtyping, monadic objects.
Online Bibliography of Haskell Research - This site provides a constantly-growing bibliography of papers, theses, etc. on research related to the Haskell programming language. Links to online copies of each paper are provided, where available.
pH (MIT parallel Haskell) - A parallel eagerly evaluated variant of Haskell with syntactic provisions for loops, barriers, and I- and M- structure storage.
Regular expressions in Haskell - Native Haskell implementation of polymorphic regular expressions. The regexps contains most of the features found in Perl.
TclHaskell - Useful for building graphical user interfaces through the Tcl/Tk. [Open Source, BSD-like]
The Glasgow Haskell Compiler (GHC) - An optimizing compiler for Haskell, written in Haskell. Includes extensions for concurrency and heap & time profiling. [Open Source, BSD-like]
The Haskell Home Page - A repository for information about the lazy functional programming language Haskell.
The HBC compiler - A compiler and interactive system for Haskell 1.4, unsupported for two years now.