Notes from 10/28/02

- quick overview of capture of free variable problem
	- substituted a y into a lambda that used y
	- then the y substituted in is different than the y inside the lambda
- solution is to change the name of one of them
- hard to change the free variable - no handle on it
- easy to systematically change the parameter and all occurences in the lambda
	- what substitute was written to do, after all
- problem is what name to use
	- (generate-uninterened-symbol) solves that problem
	- provides a name that has not been used, and cannot be used
	- impossible to input it
- free_in (convention would call this free_in?) checks to see if this is needed

- success!! - after much debugging (specially of selectors)
	- look at demo for example
	- lesson here is CHECK the selectors FIRST
	- know which selectors to use!!

- idea of enviroment
	- can be represented as a list of values associated with symbols
	- not efficient underneath, but functionality is the same