Re: [Haskell-cafe] Define variable types

Note also that Helium ISN'T Haskell; it lacks hell of a lot of Haskell98 features (not to mention common extensions). 05.02.09, 14:57, "Roman Cheplyaka" :

...

Hello,

I'm new to Haskell and it seems like a very nice language to learn. However I'm not really familiar with the errormessages it produces. I am using a Helium interpreter. I've created the following module (however it is just a small sketch). I've written the following code:

fac :: Int -> Int fac n = product[1..n]

boven :: Int -> Int -> Int boven n k = (fac n) `div` fac k * fac (n-k)

bin :: Int -> Int -> Int -> Int bin n k p |(n-k)>0 && k>0 = (boven n k) * (p^k) * (1-p)^(n-k) |(n-k)<0 && k>0 = (boven n k) * (p^k) * (1/((1-p)^(-(n-k)))) |(n-k)<0 && k<0 = (boven n k) * (1/(p^(-k))) * (1/((1-p)^(-(n-k))))

When I load this into my interpreter it says:

Compiling ./Test.hs (11,55): Type error in infix application expression : 1 / ((1 - p) ^ (-(n - k))) operator : / type : Float -> Float -> Float does not match : Int -> Int -> Int (12,47): Type error in infix application expression : 1 / (p ^ (-k)) operator : / type : Float -> Float -> Float does not match : Int -> Int -> a (12,62): Type error in infix application expression : 1 / ((1 - p) ^ (-(n - k))) operator : / type : Float -> Float -> Float does not match : Int -> Int -> a You can't use fractional division (/) with integers. You can convert integers to fractions using fromIntegral. E.g.: 1 / fromIntegral ((1 - p) ^ (-(n - k))) (literals like 1 doesn't need to be converted because they are

* Tsunkiet Man [2009-02-05 12:37:22+0100] polymorphic) -- Roman I. Cheplyaka :: http://ro-che.info/ "Don't let school get in the way of your education." - Mark Twain _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe