Notes from 10/30/02

- old lisp
	- asst. 6 is essence of eval from that
	- they made it slightly more complex
	- added eval/apply dichotomy
- was written in lisp
	- like ours is written in scheme
	- self-hosting

- static vs dynamic scope
	- static = associations in area where very was introduced
	- dynamic = associations with something near it when it's used
	- lexical = static in this context
	- only need to look at the program, not run it

- equivalence products
	- problem is multiple representations of the same thing
	- = for numbers
		- different types of things have equality tests for that type
	- equal?
		- checks for S-expr equality
	- eq?
		- great for checking symbols to other symbols
	- read the reference manual for better understanding
	- also shows difference between eq? and eqv?
	- you will usually use eq? and = + its relative

- functional programming
	- "referential transparency"
	- essentially says you can replace a sub-expr with its value and you get the same result
	- Scheme says "something that has the same value" instead of "its value"

- study Ch. 3.2
	- note: material after this point is not on the midterm

- association of symbols and values in enviroment gets broken up
	- old way: symbols --- (via enviroment) ---> values
	- new way: symbols --- (via enviroment) ---> variables or places --- (via state) ---> values