Hi The GHC Show instance of Ratio is different from that in Yhc/Hugs/The Report. There has been a discussion in the bug tracker, which you can follow at http://hackage.haskell.org/trac/ghc/ticket/1920 . I thought I'd summarise everyone's positions, and the possible actions we can take. Problem ------------- showing a Ratio using GHC places no spaces around the "%", in Hugs/Yhc/The Report it has spaces. Read the bug tracker for an example. Solution ------------ EITHER: Make all compilers put out spaces OR: Make no compilers put out spaces The alternative is to have different compilers do different things, which I think we can agree is bad (TM). As a more general point, should all infix constructors have spaces around them or not. Whatever we decide, it would be weird for it to apply to only the Ratio instance and not others. I think we should solve this problem now. It makes sense to come to some consensus which Haskell' will follow, then fix whichever set of compilers is determined to be wrong. Opinions -------------- The basic differing of opinions is should Show print the minimal ASCII representation (Neil Mitchell, Simon Marlow) or something that is slightly pretty where possible (Ross Patterson, Ian Lynagh). Comments welcome. Thanks Neil