[clean-list] Newbie Question

[Wilfried Esken]

Hello,
I tried to learn CLEAN and therefore I read the exercises in the Clean Book.
First I made a function MaxofList which should return the maximum value of a
list.

I tried it this way:

maxi :: a a -> a | <, == a
maxi a b
	| a <= b = b
	| otherwise = a

MaxofList [] = 0
MaxofList [x] = x
MaxofList [x,y] = maxi x y
MaxofList [first:rest] =
	maxi a b
	where a = first
	      b = MaxofList rest


This works fine for a list of integers, but I want to have a function like

MaxofList :: [a] -> a

This doesn't work because of
	MaxofList [] = 0,
the compiler derives type Int for the function.
What is the solution for having a generell typed function in this case?

Thank you,
Willi