Hugs Archive - Many files for Hugs Haskell interpreter: source code, documents. - http://web.cecs.pdx.edu/~mpj/hugsarc/
Gofer - Small interpreter for language based on Haskell report 1.2; experimental, more so for type classes. Haskell adopted some ideas of Gofer, but Gofer type class system is more flexible. Runs on DOS, Linux, Macintosh, Unix. Hugs predecessor. - http://web.cecs.pdx.edu/~mpj/goferarc/
Kahu Research - Makes Mondrian, light Haskell version to interoperate with other languages in OO environments; runs on .NET (old version for JVM), supports ASP.NET, to embed functional code in webpages with C#. Has version of Glasgow Haskell Compiler using Mondrian for . - http://kahu.zoot.net.nz/
Hugs98 for .NET - Extension of Hugs98 Haskell interpreter, for interoperation between Haskell and .NET and its framework; can instantiate and use .NET objects in Haskell, and vice versa, call and use Haskell functions from any .NET language. - http://galois.com/~sof/hugs98.net/
Eden - Parallel functional language to program reactive systems and parallel algorithms using distributed memory. Extends Haskell, but overrules lazy evaluation whenever needed to support parallelism; gives enough control to implement parallel algorithms efficie - http://www.mathematik.uni-marburg.de/~eden/
PolyP - Polytypic programming language; source files for compiler written in Haskell that compiles PolyP-code to Haskell; library of polytypic functions written in PolyP, some examples, documents, downloads. - http://www.cs.chalmers.se/~patrikj/poly/polyp/
The HBC compiler - A compiler and interactive system for Haskell 1.4, unsupported for two years now. - http://www.cs.chalmers.se/~augustss/hbc/hbc.html
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. - http://www.cee.hw.ac.uk/~dsg/gph/
Haskell++ - Object-oriented Haskell extension, using a preprocessor, supports a form of inheritance via extended class and instance declarations. Descriptions, documents, source download, links. - http://www.cs.chalmers.se/~rjmh/Software/h++.html
Hugs - An interpreter for Haskell which runs on almost any platform. Primarily used for teaching. - http://www.haskell.org/hugs/
Helium - A functional programming language (subset of the Haskell) and a compiler designed especially for teaching Haskell. - http://www.cs.uu.nl/helium/
Distributed Haskell - Extension for parallel and distributed programming, with combinators from concurrent constraint programming; computational parts of programs are expressed functionally, development was first for tightly coupled multiprocessors, evolved from Goffin. - http://www.cse.unsw.edu.au/~chak/goffin/
Template Haskell - Haskell 98 extension allowing type-safe compile time metaprogramming, with Haskell, as the manipulating language and the language being manipulated. - http://www.haskell.org/th/
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] - http://www.haskell.org/ghc/
pH (MIT parallel Haskell) - A parallel eagerly evaluated variant of Haskell with syntactic provisions for loops, barriers, and I- and M- structure storage. - http://www.csg.lcs.mit.edu/projects/languages/ph.shtml
Jaskell Project - Java bytecode generator backend for Glasgow Haskell Compiler (GHC), so one can build Java applets or applications via the Haskell language. - http://www.scdi.org/~avernet/projects/jaskell/
nhc98 from York - A Haskell 98 compiler. - http://www.cs.york.ac.uk/fp/nhc98/
Data Field Haskell - Dialect with instance of data fields (a generalization of arrays), useful for rapid prototyping of parallel algorithms, and parallel high-level system specification. - http://www.mrtc.mdh.se/projects/DFH/
Chameleon - Haskell-type language, implements ideas described in a 'A Theory of Overloading'. Compiles Chameleon to (plain) Haskell; can mix Haskell and Chameleon overloading. Descriptions, documents, downloads. - http://www.comp.nus.edu.sg/~sulzmann/chameleon/