Hello, my original query concerning partial application was triggered by the following statement from Thomson's "The Craft of Functional Programming", p. 185: " multiplyUC :: (Int, Int) -> Int multiplyUC (x,y) = x * y multiply :: Int -> Int -> Int multiply x y = x * y .... In the case of multiplications we can write expression like multiply 2". When I read this, I thought that you could partially apply "multiply" by typing "multiply 2" at the ghci prompt. However, this generated an error: <interactive>:1:0: No instance for (Show (Int -> Int)) arising from use of `print' at <interactive>:1:0-9 Possible fix: add an instance declaration for (Show (Int -> Int)) In the expression: print it In a 'do' expression: print it After reading http://www.haskell.org/hawiki/PartialApplication, I figured out that you can only partially apply declared functions, in source files, not at the prompt: multiplyBy2 = multiply 2 Now "multiplyBy2 50" yields "100" On page 22 of "Programming in Haskell", Howard says that you can do the following partial application of the curried function add': add' 1 :: Int -> Int, where add and add' are declared as add :: (Int,Int) -> Int add (x,y) = x + y add' :: Int -> (Int -> Int) add' x y = x + y However, typing "add' 1" at the prompt generates an error. If I add the following to my source file addOne = add' 1 typing addOne 5" at the prompt yields "6", which is the right answer. Cheers, phiroc