[Haskell-beginners] type of zipWithPlus

[Sebastian Hungerecker]

On 01.10.2010 05:43, Russ Abbott wrote:
>> let (zipWithPlus :: Num a =>  [a] ->  [a] ->  [a]) = zipWith (+)
>>      
> <interactive>:1:5:
>      Illegal signature in pattern: (Num a) =>  [a] ->  [a] ->  [a]
>          Use -XScopedTypeVariables to permit it
>    

It works if you write it as:
let zipWithPlus :: Num a => [a] -> [a] -> [a]; zipWithPlus = zipWith (+)

I.e. writing it exactly as you would in a file (inside a do-block),
but with a semicolon where the linebreak would be.