Com Sci 221 --- Programming Languages
Assignment #6 --- Autumn 2000
Due Monday, 13 November

No program execution is needed in this assignment.

1. Write a single procedure declaration and a single call to the procedure that executes correctly with no errors and produces three different results with each of call by value-result, call by reference, and call by name. Make the procedure declaration as simple as possible, and make it as helpful as possible in understanding why the three calling methods are different. State the three different results for the three calling methods. Hint: you need to pass an array reference as a parameter.



2. Consider the program of problems 5.4-5.5 (Figure 5.29) on pages 199-200 of the text.
   
   
   1. Give a very simple context-free grammar for the strings of balanced parentheses of the three types (), <>, [] whose parse trees have exactly the same shape as the activation trees for the program.
   
   
   
   2. Display the trees for the example <()(())[<>]>.
   
   
   
   3. Explain very briefly what components of the program correspond to the productions in the grammar.
   
   
   By the way, you've just invented recursive descent parsing.