CS 227 meeting -*- Outline -*-

* Why Scheme?
** a misconception
	It's a misconception that Com S 227, or Com S 228
		is a course about a language
		(a trade or skills in that langugage course)
		- Com S 228 is about data structures (C++ is a vehicle)
		- Com S 227 is about programming (Scheme is a vehicle)
	Your first task is to find out what computing is about,
		and whether you like it
		- specific language skills can wait.
	Second task is to learn a framework for continued professional growth
		- specific skills will change over time
			even in 4 years
	Note: you will learn C++ in 228, can help you get that summer job
		(I never had a summer computing job until I was a senior)

** our purpose
	to get you interested in computer science
	to show you what programming is like
	develop programming skills for the future of programming

	this is best accomplished with Scheme
		(in our experience, at the present time):
		- best textbooks
		- do the most interesting things
		- look at more of the future of programming

*** other schools teaching Scheme

	You don't just have to take our word for it...
---------------------------------
  WHAT SCHOOLS TEACH SCHEME FIRST?

MIT		Indiana
Columbia U.	Johns Hopkins
Yale		Gustavus Adolphus Coll.
Rice University Helsinki U, Finland
UCLA		U. Cal., Berkeley
U. Cal., Davis  Ryerson Polytech. Inst.
U. Oregon	Royal Inst., Sweden
Washington U.   U. of Delaware
U. Mass		U. of Br. Colum.
Iowa State	Syracuse U.
U. of Illinois

U. of Chicago   U. Geneva
Princeton U.	Queen's U. Canada
St. Olaf	Brussels Free U.
San Jose St.	U. Louisville
Monash U., Aust	Brandeis U.
Clarkson U.	Delft U., Netherlands
Landler Coll.	Northeastern U.
Oberlin Coll.	Northwestern U.
Rowan Coll.	Swarthmore Coll.
Tampere U., Fin	Technion, Israel
Trinity U.	Erlangen-Nuernberg, Ger.
U. Florida	U. Minnesota
U. Oslo, Norw.  U. Southhampton, Eng.
Wesleyan U.	U. Waterloo, Can. 
------------------------------
	Above data is as of Jan 1993

*** details on the above (omit in class)

	According to Terry Kaufman: colleges and Universities using Scheme are:
	127 colleges/universities worldwide
	    - 49 of these use Scheme in introductory courses
	85 colleges/universities USA only
	   - 35 of these use Scheme in introductory courses
	
	Sources: 1st group comp.lang.scheme and Richard Reid at MSU,
	or reliable info (personal reports);
	2nd group comp.lang.scheme only (with course number)
	(Monash university is claimed by both Scheme and C++...)
	
	According to Richard Reid, 9 other Universities
		start with similar languages
		(SML = 5, ISETL = 2).
	
	According to Richard Reid,
	as of October 1992, only 8 universites were doing introduction in C++
	
		Mich. State & Oregon State U.
		Santa Clara & U. of Birmingham, UK
		U. of Virginia & ITR, Switzerland
		Monash Univ. (?) & Wheaton U.
	
	with 21 others starting in C
	(including CMU, Duke, San Diego St., USC, Virginia Tech)
	
	124 teach Pascal, 57 Ada, 50 Modula-x,  8 Fortran, 4 Turing, none BASIC

** how Scheme helps
	How does scheme help us have more fun.
	Basically by suppressing details

*** suppressing syntactic details
-------------------------------------
      SCHEME HAS SIMPLER SYNTAX

 Scheme		       C or C++
=========================================
(+ 1 2)                1 + 2

(f 3)                  f(3)

(compose f g)

(if (= x 2) y (f y))   (x == 2) ? x : f(y)

(define x 5)	       int x = 5;

(define f              int f (int x) {
  (lambda (x)             x++;
    (add1 x)))         }
--------------------------------------
	Notice how regular the left side is,
		and how many special things are on the right?
	So we don't need to spend lots of time on the complications of such
		a language.

*** suppressing semantic details
	simpler execution model
	(the programming language does more of the boring details for you)

	evolution of technology
		- expensive features are developed
			to make humans more productive
		- eventually they become commonplace

**** Cooking analogy
	show evolution of baking ovens
		open fire (flat irons placed on a rack)
		brick ovens (and ceramic (later tin) dishes)
		coal/oil/parafin/gas stoves
		electric stoves
		theromostats
	the point: these fancy new inventions allowed the cook to make
			more elaborate pastries, and although most advances
			were more expensive to begin with, they eventually
			became very common

**** Car analogy
	also in autos expensive features make their way into popularity
		e.g., enclosed bodies (a luxury in 1903),
			electric starters,
			automatic transmissions,
			power steering, power brakes, etc.
	imagine learning to drive
		would you rather learn on an expensive to operate racing car
			or on a car that you can afford?

**** programming languages

-----------------
 BRIEF HISTORY OF PROGRAMMING LANGUAGES

1945-50 machine language
		1107:  46  1112   1061
1950s   assembly language
		Loop:  add 11,12
1957, Apr.  FORTRAN I
		1107   I = 11 + 12
1957, Sept. FORTRAN II
		subroutines
1960  LISP 1.5
		recursion, if-exprs.
1963        FORTRAN IV
1975  Scheme
		lambda closures
1977        FORTRAN 77
		structured primitives
1990	    FORTRAN 90
		recursion, array ops
-----------------
	moral: when you program it may always be called FORTRAN,
		but it will have more and more of the features of Scheme