-- check strings for being palindromes

pal :: String -> Bool
pal str = reverse low == low
          where low = lower (filter isAlpha str)

lower str = map toLower str

f x = x + 2 * x - 3 + y
      where y = x * x


panama = "A man, a plan, a canal ... Panama!"

-- "A man a plan a canal Panama" 
-- "A man, a plan, a canal ... Panama!"


tests = [ panama, "Bob", "x", "", "Madam, I'm Adam" ]

check = all pal tests