Lecture 4, CSE341, Spring 2004 summary

* "One of" types vs. "Each of" types
   * what operations each should have
   * synergy from combining the ideas
   * brief comparison with OO classes (will come back to this)
   * some jargon for this (sum types, product types, constructors, ...)

* Record types in ML
   * just another "Each of" type

* User-defined types in ML
   * datatype and case
   * type synonyms
   * lack of need for built-in tuples and lists

* More on pattern-matching
   * the "built-in" way for testing "One of" variants
   * elegant and preferable style
      * check for impossible cases
      * check for inexhaustive matches