type of (/) ?

[Christian Maeder]

Yaroslav Korchevsky wrote:
> my_avg list =  (accum list) / (length list)
> ================================

> ERROR "U:\slav\FP\Avg.hs":11 - Type error in application
> *** Expression     : accum list / length list
> *** Term           : accum list
> *** Type           : Float
> *** Does not match : Int
>  
> Why "accum list" should match to "Int"?

(/) expects two equally typed arguments
and (length list) yields the type Int.

> When I try to replace (length list) with number - it works.
>  
> ================================
> my_avg list =  (accum list) / 5 --works fine
> ================================
> xx = 5
> my_avg list =  (accum list) / xx --doesn't work
> -- same message as above

Try to check the type of 5 and xx using ":t" at the hugs prompt.

> Possibly, I don't know something important, or Hugs is not quite mature?

Haskell does at least allow literal numbers to fit several types.

HTH Christian

P.S. fromIntegral can be used for conversions