libghc6-src-exts-dev | Haskell-Source with eXtensions library for GHC6 | Mehr ...
haskell-src-exts (HSX, haskell-source with extensions) is an extension of the standard haskell-src package, and handles most common syntactic extensions to Haskell, including: * Multi-parameter type classes with functional dependencies * Empty data declarations * GADTs * Implicit parameters (ghc and hugs style) * Template Haskell (broken for 6.4, needs redoing)