Haskell Pattern Matching

not :: Bool -> Bool   
not False = True   
not True = False  
  
-- Operator   
(&&) :: Bool -> Bool -> Bool    
True  && x = x   
False && _ = False  

Patterns mit Tupeln

fst :: (a,b) -> a   
fst (x,_) = x  
  
snd :: (a,b) -> b   
snd (_,y) = y