haskell@gentoo.org Gentoo Haskell This library provides a quick-and-dirty (but often effective) method for extending Haskell's syntax using a custom preprocessor. It parses Haskell into a bare-bones AST with just enough knowledge of the syntax to preserve nesting, and then allows transformations on the AST. See the package ixdopp (<http://hackage.haskell.org/cgi-bin/hackage-scripts/package/ixdopp>) for an example of how to do this.