CS 342 Lecture -*- Outline -*-

** CLU
	advert: language used to study data abstraction
		single most important idea in programming
				(aside from procedures)
			why? because it allows programmers to think abstractly
				about data structures
				because it mitigates the effect of
				most common changes to programs
				(change of data structure)
        we're not covering Ada explicitly, but Ada is a lot like CLU
		but may find it helpful to read about Ada anyway

*** History and Goals

	------------------------
        1968 Algol 68 (lots of coercions, negative influence)
        (1970s were the golden age of language design, "structured prog")
        1971 Pascal
        1971 Parnas begins promoting notion of information hiding (modularity)

        1973 Barbara Liskov's group at MIT begins design of CLU
        1975 initial verision of CLU implemented
                no exception handling
        1978 essentially final version of CLU
	------------------------

        "The goal was to work out data abstraction precisely." - B. Liskov
                i.e., support programming method based on data abstraction
        also support other ideas about programming: no global variables