CSC302 2007S, Class 26: Continued Discussion of Mid-Semester Examination

Overview:
* What should we do?
* Problem 3, continued.
* Problem 4.
* About Presentations (if time).

Admin:
* Don't forget to respond to the three readings for Friday.  
  * If you have trouble reacting, then you might consider 
    * rhetorical style of the pieces
    * syntactic choices (and Ruby certainly makes different 
      syntactic choices)
    * differences in model of object between Ruby and Java.
* We'll doing some planning for presentations if there is time.
* Plans for Ruby: On Friday, we'll do a lab.  Next week, we'll discuss
  relationships between Ruby and other object-oriented languages you
  know.  You'll probably have no new reading for Monday and
  a separate reading for Wednesday.
* I've been asked to meet with a department at 11, so I will be 
  unavailable for office hours.

What should we do?
* Problem 1: I WANT YOU TO LEARN; EVIDENCE FROM EXAM IS THAT YOU DIDN'T
  * Need more practice before an exam.  Sam shouldn't put stuff on an
    exam that you haven't had a homework assignment about.
  * Small reflection/discussion questions but not something that Sam
    would grade
  * Clarify bottom level
* Problem 2: NEITHER OF US WANT YOU TO HAVE BAD GRADES
  * Don't penalize us because we haven't practiced enough
  * Exams should have simple "do you understand the basics" questions
  * Also "hard, interesting questions", perhaps real-world problems

CHECK OF UNDERSTANDING

in _l_eval_cond
* What other error checking might you add?
* How can you replace the recursion with a while?

in _l_eval_lambda
* How would you write evlis, pairup, append, and the rest
* What other error checking might you add?