fib.hs

-- defines the fibonacci function, takes an integer and returns the fibonacci number
fib :: Int -> Int
fib n = if n <= 2 then
          n
        else fib (n - 1) + fib (n - 2)

-- define a infinit list of all fibonacci numbers
fibs :: [Int]
fibs = map fib [1..]

-- prints the tenth number in the list of all fibonacci numbers
main = print (fibs !! 10)