Edited by author 03-13-2004 09:15 PM
Hey Sean or Fox,

Could you list a couple differences between Objects in Java and Records as defined by Sethi (if there are any).

Thanks,

Amir

Ms. Iqua -- You should know the cool trick that underlies them: that you use variables as parts of lists, then fill those in later. An easier example is inserting items in the back of a list:
    X = [1,2|Y],
    Y = [3,4|Z].
here we leave a hole in X, named Y, then put [3,4] into that hole, leaving a new hole named Z. To test your understanding, you should try to explain difference lists in terms of their creating and filling a hole in a list.

Amir -- To answer your question with a question, the EBNF for statements with a terminator is:
    stmts: { <stmt> <terminator> }*
while that for a separator is:
    stmts: { <stmt> { <separator> <stmt> }* }?
BTW, I don't think you're right about the semicolon in Java; and there's not much to know about sep. vs. term. -- just the definitions.

What is the difference between a terminator and a separator. What are the major differences between them and what would you expect that we would need to know with regards to this topic for the final.

My current understanding is that terminator ends a sequence of code, for example the way a bracket would in java. But, a seperator would seperate segments/lines of code much as a semi-colon would in java.

Do we need to know difference lists for the final? And if so, to what extent?

Edited by author 03-13-2004 04:12 PM
Thanks Sean.

Amir -- Not even in a disjunction, like "Do you want to be social, or do some more programming?" "Social" here is meant in the broader sense that programming languages are products and producers of culture. For example, your familiarity with Java is due largely to social factors like Sun's successful marketing campaign and UCSD's desire to meet perceived industry needs. Students in 5 years will likely be learning C# for similar reasons, which have nothing to do with technical merit. It goes the other way, too -- thousands of Perl programmers socialize at Perl conferences around the world, having been brought together by their common choice of programming language. And the language used to express algorithms strongly influences what algorithms can be expressed, and how easily. Like human languages, programming languages live and die by their users, and in turn influence what these users can say and do.

Abstraction... Think about modules, classes, and objects as units of data abstraction, and blocks, control structures, and procedures as units of control abstraction. Each lets you hide some details of how some data is structured, or how a task is performed. When looking at some language, you should ask yourself what mechanisms it provides for control and data abstraction, and how they differ from the corresponding facilities in other languages. For example, Fortran doesn't do much in the way of control and data abstraction, but does at least have subroutines. C has procedures, blocks, and structured control, all mechanisms of control abstraction that Fortran lacks.

Does anybody have an clue to what is meant by the "social use of programming and programming languages." I don't generally put programming and social in the same sentence, so I'm not really sure how to interpret this.

Secondly, any idea what specifically we need to know as it relates to abstraction. Abstraction, in the outline, is placed within the Introduction, but there is really no discussion about abstraction (or it's definition) in the pages of the book or notes.

Thanks a lot.

Amir

If your Prolog assignment was scored "0" because it was the same as another student's assignment, and you spoke to me during the review session today, please email me.

Hi Everyone,

I hope that our review session and discussion sections were useful. Personally, I would like to make them even more useful in the future. If you have a chance, feel free to send some feedback for future reference.

Good luck (skill) on the final!

Fox

Please explain more about unification, since the previous final includes a question about this, but it seems to be very confusing .

I second the cut. The text is really confusing, it'd be great to get an explanation of it during the review session tmw.

I still don't understand what ! (cut) does in prolog. If this is important in doing well in the final, I would like to see an example on it.

A student emails me:

> pg. 332 Sethi: Type Names and Type Equivalence
> I didn't understand any of the conditions. They seem so vague, do you
> think you could provide an example?

Does any of you have a response, or further questions along these lines? Note that this is material from the first half, and so will be covered less heavily by the final than the more recent material.

"Prolog(ue) to a beating"? Or, for all the optimists out there (where?), "prolog to superior test-taking action"?

"Amalog: Prolog for amateurs"?

Seriously, you guys' posting (and answering!) questions on the webboard will make the review much more productive, both because we can prepare for them in advance, and because seeing others' questions can help you refine your own. So post away, and we will collect and (try to) address the question tomorrow.

I concur.