eqlist.rkt

#lang sicp

(define (atom? x)
  (and (not (null? x))
       (not (pair? x))))


;(atom? 'a)
;(atom? 1)
;(atom? '())
;(atom? '(1))
;(atom? '(1 2))

(define eqan?
(lambda ( a1 a2)
(cond
((and (number? a1) (number? a2))
(= a1 a2))
((or (number? a1) (number? a2))
#f)
(else ( eq? a1 a2)))))
(display "equan? ")
(eqan? 1 '1)

(define (eqlist l1 l2)
  (cond
    ((and (null? l1)(atom? l2)) #f)
    ((and (atom? l1)(null? l2)) #f)
    ((and (pair? l1)(atom? l2)) #f)
    ((and (atom? l1)(pair? l2)) #f)
    ((and (null? l1)(pair? l2)) #f)
    ((and (pair? l1)(pair? l2))
     (and (eqlist (car l1) (car l2))
          (eqlist (cdr l1) (cdr l2))))
    (else (eq? l1 l2))))

(eqlist '(((test)) test) '(((test)) test)) (display "should be #t")
(eqlist '() 'a) (display "should be #f")
(eqlist '() '()) (display "should be #t")
(eqlist '(a) '()) (display "should be #f")
(eqlist 'a 'b) (display "should be #f")
(eqlist 'a '(a)) (display "should be #f")
(eqlist 'a '())(display "should be #f")
(eqlist 'a 'a)(display "should be #t")
(eqlist '(a v) '())(display "should be #f")
(eqlist '(a b) '(a b))(display "should be #t")
(eqlist '(strawberry ice cream) '(strawberry ice cream))(display "should be #t")
(eqlist '1 1)(display "should be #t")

(define (equlist? l1 l2)
  (cond ((and (null? l1)(atom? l2)) #f)
        ((and (null? l1)(null? l2)) #t)
        ((null? l2) #f) ;we know if anything is null it's bad since we checked both
        ((and (atom? l1)(atom? l2)) ;no need to check atom l1 null l2
         (eqan? l1 l2))
        ((and (atom? l1)(atom? (car l2))) #f)
        ((atom? l2) #f) ;we know both aren't atoms so only other thing is l1's car is  list              
        ((and (atom? (car l1))(atom? (car l2)))(equlist? (cdr l1)(cdr l2)))
        (else (and (equlist? (car l1)(car l2))(equlist? (cdr l1)(cdr l2))))
))
(newline)
(display "equlist?")
(newline)
(display "should be #t")(equlist? '(((test)) test) '(((test)) test))
(display "should be #f")(equlist? '() 'a)
(display "should be #t")(equlist? '() '())
(display "should be #f")(equlist? '(a) '())
(display "should be #f")(equlist? 'a 'b)
(display "should be #f")(equlist? 'a '(a))
(display "should be #f")(equlist? 'a '())
(display "should be #t")(equlist? 'a 'a)
(display "should be #f")(equlist? '(a v) '())
(display "should be #t")(equlist? '(a b) '(a b))
(display "should be #t")(equlist? '(strawberry ice cream) '(strawberry ice cream))
(display "should be #t")(equlist? '1 1)
(display "should be #f")(equlist? '((test) test2) '(test test2))
(display "should be #f")(equlist? '(test test2) '((test) test2))