Com S 342 --- Principles of Programming Languages

		    HOMEWORK 7: OBJECTS AND CLASSES
		  (File $Date: 96/04/28 20:25:43 $)

Due: (never, as all the problems are suggested practice)

In this homework, you will learn about the semantics of object-oriented
programming languages.  All of the problems are suggested practice,
and for your own enjoyment.  Don't turn them in, although we can talk
about them with you.

The section headings below give the readings related to the problems.

ESSENTIALS OF PROGRAMING LANGUAGES: Section 7.1

1. (suggested practice) [OO allows multiple implementations in a program]
   Do exercise 7.1.1. 
   You can get the interpreter for this section by executing:
	(load-from-lib "ch7-1.scm")

2. (suggested practice)  [queue in the defined language]
   Write and test a class for queues in the defined language.

3. (suggested practice)  [methods vs. procedures]
   Do exercise 7.1.2.

4. (suggested practice)  [making self an instance variable]
   Do exercise 7.1.7.

5. (suggested practice)  [instance variables without &]
   Do exercise 7.1.9.


ESSENTIALS OF PROGRAMING LANGUAGES: Section 7.2

6. (suggested practice)  [count instances of stackclass]
   Do exercise 7.2.1.

7. (suggested practice)  [make self be treated like super]
   Do exercise 7.2.2.

8. (suggested practice)  [dynamic inheritance of variables]
   Do exercise 7.2.4.

9. (suggested practice)  [initializations calling super's initailize]
   Do exercise 7.2.5.

10. (suggested practice)  [multiple inheritance]
   Do exercise 7.2.6.  This will be hard, as it may require
   changing the parser.