-- the main was a function in the last example, but here 
-- are other more normal functions (very very simple ones)

-- first something that is not really a function, 
-- this takes nothing as a parameter, and returns an Int
function1 :: Int                   -- defintion
function1 = 5                       -- code

-- functions always have types, so an implicit defintion. Haskell is quite clever and can often 
-- figure out what is going on without you, however it is better practice to define ever function 
- clearly.

-- now a function that takes one parameter and returns another
function2 :: Int->Int
function2 x = x+4               -- Ok, really dull

-- more complex
function3 :: Int->Int
function3 x = x*x+5

-- functions with more than 1 parameter
function4 :: Float->Float->Float
function4 x y = x*y+(y*5)

-- functions calling other functions
function5 :: Float->Float->Float->Float
function5 x y z = (function4 x y) + z

-- the where statement, it is often useful for readability
-- to write your functions like this
function6 :: Int->Int->Int
function6 x y = z+m+p 
  where
    z = x+y
    m = x*y
    p = x*x*x

-- entry point for the compiler (required to compile)
main :: IO()
main = do putStrLn (show function1) 
          putStrLn (show (function2 2)) 
          putStrLn (show (function3 2)) 
          putStrLn (show (function4 2 2)) 
          putStrLn (show (function5 2 2 2)) 
          putStrLn (show (function6 2 2))