http://hackage.haskell.org/trac/haskell-prime/wiki/DoAndIfThenElse says (and my memory seems to agree) that GHC has been changed to accept things like readnums f n = do eof <- hIsEOF f if eof then return n else do l <- hGetLine f readnums f (n + read l) where the `then' and `else' are aligned with the `if' rather than being slightly more indented as the Haskell 98 standard requires. Yet, when I try it with GHCi 6.8.2 I get an error: Prelude> :load "/home/monnier/tmp/foo.hs" [1 of 1] Compiling Main ( /home/monnier/tmp/foo.hs, interpreted ) /home/monnier/tmp/foo.hs:6:18: parse error (possibly incorrect indentation) Failed, modules loaded: none. Prelude> Does anybody know what's up with that? Stefan