Define Haskell function with let fun x = x + 1 form

Question

If I have a function as following:

f::[a]->Integer
f  [] = 0
f (x:cx) = 1 + (f cx)

how can I define the function inside the main with 'let'?

I know I can define a function inside main: eg

let f x = x + 1

but how I'm pattern-matching for "f [] = 0" ?

Thanks

Answer 1

You can still do it the same way:

main =
    let f  [] = 0
        f (x:cx) = 1 + (f cx)
    in
    print (f "abc")

or

main =
    let
        f  [] = 0
        f (x:cx) = 1 + (f cx)
    in
    print (f "abc")

The crucial part is that the f s in the two equations must line up and be indented more than let .