Here are some examples of pattern matching in Haskell.

patternMatch.hs

-- Haskell will match starting at the top, until it hits a catchall
factorial :: Int -> Int
factorial 0 = 1
factorial n = n *  factorial(n - 1)

-- Haskell is able to match empty lists and x:xs patterns
head' :: [a] -> a
head' [] =  error "No head available on empty lists!"
head' (x:_) = x

-- Here we use a type class to make sure we can convert the input (inner) types to strings
tell :: (Show a) => [a] -> String
tell [] = "Empty"
tell (x:[]) = "Contains only 1 item: " ++ show x
tell (x:y:[]) = "Contains only 2 items: " ++ show x ++ " and " ++ show y
tell all@(x:y:_) = "Contains many items... "++ show all

tell [1, 2, 3, 4]
-- "Contains many items... [1,2,3,4]"

-- Here is a variation on tell using [Char]
tell' :: String -> String
tell' "" = "Empty"
tell' all@(x:xs) = all ++ " -- first letter: " ++ [x] ++ " remaining letters are: " ++ xs