C311 Spring 1997 -- Programming Languages

Assignment 2: Static Properties

Due Tuesday, February 4, 11:59P

1. EOPL Exercise 2.3.1, bound-vars procedure

   > (bound-vars '((lambda (x) x) y))
   (x)
   > (bound-vars '((lambda (x) x) x))
   (x)
   > (bound-vars '((lambda (x) x)(lambda (x) x)))
   (x)
   > (bound-vars '(lambda (x) (y (lambda (y) (y x)))))
   (x y)		; or perhaps (y x)
   	  

2. EOPL Exercise 2.3.2, bound? procedure

   > (bound? 'x '(lambda (x) x))               
   #t
   > (bound? 'y '(lambda (x) y))               
   #f
   > (bound? 'x '((lambda (x) x) x))           
   #t
   > (bound? 'x '((lambda (y) x) x))           
   #f
   > (bound? 'x '((lambda (x) y) y))           
   #t
   > (bound? 'x '((lambda (x) y) (lambda (y) x))) 
   #t
   > (bound? 'x '(lambda (x) (lambda (y) x)))  
   #t
   > (bound? 'x '(((lambda (x) y) (lambda (y) x)) (lambda (x) x))) 
   #t
   	  

3. EOPL Exercise 2.3.10

   For variable references v that are free in the expression, replace the variable reference with the list (v : free).

   > (lexical-address 'a)
   (a : free)
   
   > (lexical-address '(+ a b))
   ((+ : free) (a : free) (b : free))
   
   > (lexical-address '(lambda (a b c)
   		     (if (eq? b c)
   		       ((lambda (c) (cons a c)) a) b)))
   (lambda (a b c)
     (if ((eq? : free) (b : 0 1) (c : 0 2))
         ((lambda (c)
            ((cons : free) (a : 1 0) (c : 0 0))) (a : 0 0))
         (b : 0 1)))
   
   > (lexical-address
      '(lambda (a b c)
         (lambda (d e)
           (lambda ()
             (+ a b c d e f)))))
   (lambda (a b c)
     (lambda (d e)
       (lambda ()
         ((+ : free)
          (a : 2 0)
          (b : 2 1)
          (c : 2 2)
          (d : 1 0)
          (e : 1 1)
          (f : free)))))
   	  

Submission

Write your answers to the exercises in a file (following the indentation rules), and send that file to

c311@lakshmi.cs.indiana.edu

handin 2

Mail -s "handin 2" c311@lakshmi.cs.indiana.edu < two.ss