Sigbjorn:
: > The question is what should 0x80000000 :: Integer
: > become when its coerced into an int.
: >
: > GHC takes the lowest 32 bits.
: > Advantage: Equality above maxBound still "works" aka above.
: > Disadvantage: 0xffffffff + 1 == 0 !
: >
: > Perhaps constant Int's larger than maxBound (or smaller
: > than minBound) should be a compile time error?
: >
:
: Int arithmetic is modulo maxBound (at least that's what
: ghc and Hugs implements), so making the Integer->Int conversion
: fall into line with that, has some merit.
On my machine the following program:
> main = do putStr "According to ghc-4.02 (1-maxBound)^2 = "
> putStr $ show mult1
> putStr "\nAccording to ghc-4.02 (maxBound-1)^2 = "
> putStr $ show mult2
> where mult1, mult2 :: Int
> mult1 = (1-maxBound)*(1-maxBound)
> mult2 = (maxBound-1)*(maxBound-1)
outputs:
According to ghc-4.02 (1-maxBound)^2 = 4
According to ghc-4.02 (maxBound-1)^2 = 4
Mod maxBound the result of both multiplication should have been 1.
Maybe it is better to rely on Integers.
Regards,
Marc van Dongen
