> how can I convince the Language.Haskell.Parser to accept "GHC Haskell" > (i.e., -fglasgow-exts, e.g. for existential types) You use my haskell-src-exts package instead. :-) http://hackage.haskell.org/cgi-bin/hackage-scripts/package/haskell-src-exts-0.3.3 Cheers, /Niklas