data Mood = Blah | Woot deriving Show

changeMood :: Mood -> Mood
changeMood Blah = Woot
changeMood _    = Blah

myAbs :: Integer -> Integer
myAbs x = if x < 0 then negate x else x

f :: (a,b) -> (c,d) -> ((b,d), (a,c))
f t1 t2 = ((snd t1, snd t2), (fst t1, fst t2))

addStuff :: Integer -> Integer -> Integer
addStuff a b = a + b + 5

subtractStuff :: Integer -> Integer -> Integer
subtractStuff x y = x - y - 10

subtractOne = subtractStuff 1
