CS 227  Lecture  -*- Outline -*-

* Introduction to Chapter 7
	
	Abstracting the structure of procedures.

** Schemes of Programs
	
	We have seen a lot of patterns or schemes
	  of programming so far: for example...

*** different schemes of recursion
	
	Have students list them:
		recursion over flat lists, non-empty flat lists
		recursion over trees, non-empty trees
		simultaneous flat or tree recursion
		numeric recursion

*** Schemes for iteration

	-- accumulators

** Never write the same thing twice

	-- Computers are good for eliminating drudgery,
		doing the same thing over and over.

	-- So in programming, we would like to write down
		such schemes of programming once and for all,
		then use them.

	Advantage of doing this is that you only have to check it once
		don't repeat yourself, so easier to do things.

	Analogy: in English, to describe something complex, give it a name
			e.g., a waltz, football, love, gravity, ...

** toolmaking
	programming is capturing patterns of information movement (relations)
		and making them available to users,
	this is also what a language designer does, but at a higher level
		(captures patterns of programs, makes them available easily)

	-- In this chapter, we see that lambda is a general
		purpose tool for capturing such schemes,

	-- That is what lambda does, it captures some
		computational scheme.
		i.e. lambda is a general purpose tool maker

	-- Our goal in this chapter is to learn to capture
		such schemes, using lambda.