[Haskell-beginners] Calling "zipWith" using "^" function.

Max Voit max.voit+mlhb at with-eyes.net
Mon Nov 9 08:59:25 UTC 2015


On Sun, 8 Nov 2015 23:14:11 -0500
Venu Chakravorty <c.venu at aol.com> wrote:

> <interactive>:1:19:
>     Ambiguous type variable `a' in the constraints:
>       `Fractional a' arising from a use of `/' at
> <interactive>:1:19-44 `Integral a' arising from a use of `^' at
> <interactive>:1:20-24 Probable fix: add a type signature that fixes
> these type variable(s) ============================
 
> Could somebody please throw some light?

Consider the types of both (^) and (/). Then take a look at

  https://www.haskell.org/onlinereport/haskell2010/haskell2x.png

and compare with your error message. Note especially that there is no
connection from Integral to Fractional or vice versa.

As a solution use either the already suggested (**) or fromIntegral
(mind the last subsection of 
https://www.haskell.org/onlinereport/haskell2010/haskellch6.html )

best,
Max


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