Home Page for CIS 624 (Programming Languages)

Midterm Solution

0-9
10-19  *
20-29  *
30-39
40-49  **
50-59
60-69  *
70-79  ******
80-89  *********
90-99  **
100-   **

Max: 101
Min: 12
Avg: 76

Syllabus

Assignments

Code

Announcements:

• Here is a little example that illustrates the difficulty in implementing finally. Incorrect implementations (including the solution that I posted) will evaluate to 1. Correct implementations will evaluate to 2:

  newexception xxx in newexception yyy in 
  let x = 1 in 
  let g = proc (z) (raise xxx x) in
  let f = proc (z) tryhandlefinally yyy
  			          (proc (a) BADERROR)
  	         in g(999)
   	         finally (x:=2) in
  tryhandle xxx 
  	  (proc (a) x)
  in f(999);
  

• Chapter 2 of my thesis has a history of continuations that you might find useful (specially pages 12-15).
• The Scheme report is available online (in ps.gz format). A slightly older version is available as a University of Oregon technical report.
• As predicted, there was a bug in the scanner. It was checking for \n but not for \r or \f. I fixed one file coreScheme/Syntax/TokenStream/TokenStream.java that you should copy.