Manlio Perillo wrote:
The first difference is about a `mod` b, when a and b are Float types. Python use the fmod function, and it also implement divmod; Haskell seems to lack support for this operation.
Yes, Haskell does not implement the full IEEE. There are differing opinions about that: some say we should add it all in, and some say we should take it all out. Floating point is ugly, but useful. It seems that enough of IEEE is implemented for the vast majority of applications, so far.
fac(777) / fac(777) 1.0 Here CPython does not convert the two integers to float before to divide
The second difference is about the division of two integers. them, but make use of a special algorithm. GHC, instead, returns NaN
No, actually here Haskell shines. Perhaps this GHCi session will illuminate the issue for you: Prelude> let fac n = product [2..n] Prelude> fac 777 `div` fac 777 1 Prelude> fac 777 / fac 777 NaN In Haskell, the various integral and floating point types are completely separate. The literal 777 is overloaded - its type is 777 :: Num a => a so it can be used for both integral and floating point types. But the division operators are separate: div :: Integral a => a -> a -> a (/) :: Fractional a => a -> a -> a So when you use 777 together with /, the 777 is interpreted as a Fractional (defaulting to Double). And when you use it with div, the 777 is interpreted as an Integral (defaulting to Integer). Hope this helps, Yitz