1. (28 pts) Using the C++ programming language, indicate the binding time (language design, language implementation, compilation, link, run, etc.) for each of the following attributes. Justify your answer.
(a) The variable declaration that corresponds to a certain variable reference (use)
(b) The range of possible values for integer numbers
(c) The meaning of char
(d) The address of a local variable
(e) The address of a library function
(f) The referencing environment of a function passed as a parameter
(g) The total amount of memory needed by the data in a program
2. (24 pts) Can a language that uses dynamic scoping do type checking at compile time? Why? Can a language that uses static scoping do type checking at run time? Why?
3. (24 pts) Does Scheme use static or dynamic scoping? Write a short Scheme program that proves your answer.
4. (24 pts) Consider the following pseudo-code:
x : integer; -- global
procedure set_x (n : integer)
x := n;
procedure print_x
write_integer (x);
procedure foo (S, P : procedure; n : integer)
x : integer;
if n in {1,3}
set_x(n);
else
S(n);
if n in {1,2}
print_x;
else
P;
-- main program
set_x(0); foo (set_x, print_x, 1); print_x; set_x(0); foo (set_x, print_x, 2); print_x; set_x(0); foo (set_x, print_x, 3); print_x; set_x(0); foo (set_x, print_x, 4); print_x;
Assume that the language uses dynamic scoping. What does this program print if the language uses shallow binding? Why? What does it print with deep binding? Why?
Note: At exactly one point during execution in the deep binding case, the program will attempt to print an uninitialized variable. Simply write a “?” for the value printed at that point.
