Lecture 9, CSE341, Spring 2004 summary

* Finish up uses of first-class functions, especially currying

* The callback idiom (and a digression into mutable state)

* Connection between n-tuples and currying

* Special syntax for currying

* Mutual recursion
  * basic example
  * good style for recurring over mutually recursive types
  * good style for finite state machines (tail recursion key)