[Haskell-cafe] pair (f,g) x = (f x, g x)?

I came across a haskell function on a book defined as following: pair :: (a -> b,a -> c) -> a -> (b,c) pair (f,g) x = (f x,g x) I thought x would only math a single argument like 'a', 1, etc....,but it turned out that it would match something else, for example, a pair as below: square x = x*x pair (square.fst,Char.toUpper.snd) (2,'a') (4,'A') The type declaration of pair is what confused me, pair :: (a -> b,a -> c) -> a -> (b,c),it says this function will take a pair of functions which have types of a->b,a->c,which I would take as these two functions must have argument of the same type, which is a,and I didn't think it would work on pairs as in the above instance,but surprisingly it did,can anybody enlighten me? -- X.W.D