[Haskell-cafe] Polymorphic addition function with variable number of arguments?
haskellie at gmail.com
Tue Mar 13 18:29:32 CET 2012
I'm trying to define a polymorphic "add" function which takes a variable
number of arguments (instance of Num) and returns their sum. I don't want
to specify the types of the arguments while calling the function, I just
want to , at most, specify the return type (*it should infer that the
return type is the type of the arguments*).
class Add a b where
add :: a -> b
instance Num a => Add a a where
add = id
instance (Num a, Add a b) => Add (a -> b) where
add x y = add (x + y)
Can someone tell me why this is not working and propose a fix for this, if
Thanks in advance
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