News

April 29:
There were two questions during recitation about the Prolog Project.

What should be the result of s([a], X)?
For part 1, the result should be obvious. For part 2, the result should be X = [[startopen, a, closeend]].
What should be the result of smash(a, X)?
The result of smash is always a list of elements (whose nesting lists have been removed). Thus, the result is X = [a].
If you want to pick up your second midterm exam, come see me during office hours. Good luck on the final exam!
April 23:
Regarding the Prolog Project, here's a breakdown of the updates for each question.
1. Unchanged; remains 80% of total score.
2. Now considered extra credit and worth 5%.
3. Will be worth 20% of total score. The input string will be generalized to include any number of nested lists (ie, lists of lists of lists …). The smash function must be a deep recursive function. The result should be a unique match (ie, typing a semicolon to ask for alternatives should return none). Here is an example query:
```
| ?- smash([a, [b], [[c]], [[[d, e], f]]], X).

X = [a,b,c,d,e,f] ? ;

no
```
You should also include a README file which will be worth 5% extra credit.
April 22:
Professor Paull's illness last week has led to several changes to finish off this course. In essence, my updates last week were obsolete one day after I posted them. Here are this week's updates.
- Project 2 has been graded and scores will appear soon on Gradebook. The scores reflect a lateness penalty of 20% for each day late. I used 16 test cases. If you want to know more details about your score, come talk to me during office hours. Some common errors were messing up the symbol table or assuming the grammar does not include spaces. Virtually every modern language uses spaces to separate tokens. Suppose I have an input string (z = a + b). Now suppose I made a typo and forgot the operator (z = a b). If there are no spaces, then (z=ab) will be accepted by the grammar but not what I intended.
- The Final Exam will be held during the last regular class meeting on Thursday, May 1, 6:40-8:00. It will be cumulative of all material in the course and will include material from the remaining lectures given by Professor Ryder and Professor Kremer.
- The Prolog Project is due on May 5, 23:59:59 (before midnight) with no extensions. You may submit up to one day late for 20% penalty.

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