Hi, if I try to use zip-comprehension, it works as long as I do it in a "fresh" Hugs. As soon as I load anything - it doesn't seem to matter what - I get INTERNAL ERROR: translate The problem occurs under both Windows NT 4 / Windows 2000 __ __ __ __ ____ ___ _________________________________________ || || || || || || ||__ Hugs 98: Based on the Haskell 98 standard ||___|| ||__|| ||__|| __|| Copyright (c) 1994-2001 ||---|| ___|| World Wide Web: http://haskell.org/hugs || || Report bugs to: hugs-bugs@haskell.org || || Version: December 2001 _________________________________________ Hugs mode: Restart with command line option +98 for Haskell 98 mode Reading file "D:\Languages\Haskell\\lib\Prelude.hs": Reading file "D:\Languages\Haskell\code\debruijn.hs": Hugs session for: D:\Languages\Haskell\\lib\Prelude.hs D:\Languages\Haskell\code\debruijn.hs Type :? for help Main> [(x,y) | x<-[0,1,2] | y<-[3,4,5]] INTERNAL ERROR: translate Main> Kind regards, Joachim Wolf Laudien