[Haskell-cafe] Showing Data.Ratio - different on GHC vs Hugs/Yhc
Hi Under Hugs and Yhc, showing a Ratio 1%2 gives 1 % 2. Under GHC showing 1%2 gives 1%2. Does the standard say anything about this? Is someone wrong? And how do Yhc/nhc/Hugs pass Bernouilli in the Nofib suite given that the output doesn't match? Thanks Neil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Showing Data.Ratio - different on GHC vs Hugs/Yhc
On Nov 16, 2007 2:12 PM, Neil Mitchell [EMAIL PROTECTED] wrote: Under Hugs and Yhc, showing a Ratio 1%2 gives 1 % 2. Under GHC showing 1%2 gives 1%2. Does the standard say anything about this? Is someone wrong? And how do Yhc/nhc/Hugs pass Bernouilli in the Nofib suite given that the output doesn't match? Judging by the Read instance, the whitespace isn't considered significant. Prelude Data.Ratio map read [1%2, 1 % 2, 1 % 2 ] :: [Rational] [1%2,1%2,1%2] -- Dave Menendez [EMAIL PROTECTED] http://www.eyrie.org/~zednenem/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Showing Data.Ratio - different on GHC vs Hugs/Yhc
Neil Mitchell wrote: Hi Under Hugs and Yhc, showing a Ratio 1%2 gives 1 % 2. Under GHC showing 1%2 gives 1%2. Does the standard say anything about this? Is someone wrong? Yes, ghc is wrong here, the Haskell 98 report [1] specifies: instance (Integral a) = Show (Ratio a) where showsPrec p (x:%y) = showParen (p ratPrec) (showsPrec (ratPrec+1) x . showString % . showsPrec (ratPrec+1) y) While it doesn't really matter, it is a deviation from the standard. I would personally prefer it if rationals were shown as 1%2, because the space is not needed, and other show instances such as lists don't insert spaces either. [1]: http://haskell.org/onlinereport/ratio.html Twan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
