gistfile1.hs

{-
        f . g x . h $ y                   f . g x . h y

               ($)                            (.)
               / \                            / \
              /   \                          /   \
            (.)    y                        f    (.)
            / \                                 .´ `.
           /   \                              .´     `.
          f    (.)                        (appl)     (appl)
               / \                         / \         / \
              /   \                       /   \       /   \
           (appl)  h                     g     x     h     y
            / \
           /   \
          g     x
-}



  Definitions:

    f (appl) x = f x     -- function application, highest precedence, left-associative
    f $ x = f x          -- function application, lowest  precedence, right-associative
    (f . g) x = f (g x)  -- function composition, middle  precedence, left-associative