Ticket #3304: gcd_0_0_haskell98.patch

File gcd_0_0_haskell98.patch, 1.1 KB (added by daniel.is.fischer, 4 years ago)

Patch for the haskell98 library

  • Prelude.hs

    commit 7a4246791fb14ca63bb23fd7f7b2d8cf6a9a4b2f
    Author: Daniel Fischer <[email protected]>
    Date:   Tue May 17 23:01:47 2011 +0200
    
        Add old behaviour of gcd
        
        The behaviour of gcd was changed to "gcd 0 0 = 0", here we must keep
        the haskell98 behaviour and raise an error.
    
    diff --git a/Prelude.hs b/Prelude.hs
    index a09a300..44342a0 100644
    a b import GHC.Base 
    151151import Text.Read
    152152import GHC.Enum
    153153import GHC.Num
    154 import GHC.Real
     154import GHC.Real hiding ( gcd )
     155import qualified GHC.Real ( gcd )
    155156import GHC.Float
    156157import GHC.Show
    157158import GHC.Err   ( undefined )
    seq _ y = y 
    207208catch :: IO a -> (IOError -> IO a) -> IO a
    208209catch = New.catch
    209210
     211#ifdef __GLASGOW_HASKELL__
     212-- | @'gcd' x y@ is the greatest (positive) integer that divides both @x@
     213-- and @y@; for example @'gcd' (-3) 6@ = @3@, @'gcd' (-3) (-6)@ = @3@,
     214-- @'gcd' 0 4@ = @4@.  @'gcd' 0 0@ raises a runtime error.
     215gcd             :: (Integral a) => a -> a -> a
     216gcd 0 0         =  error "Prelude.gcd: gcd 0 0 is undefined"
     217gcd x y         = GHC.Real.gcd x y
     218#endif