X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=assignment8.mdwn;h=0b53578a76286e6a5356ac46c1c1f36c2f0ef798;hp=e6c6085d309396f917b51d60cac383077f346a78;hb=0a9b2c5fb1adfa3b87e95fcbf26ee79d57ae7466;hpb=826badc8d42e8fa03f46abf36273d1daadf991e7

diff --git a/assignment8.mdwn b/assignment8.mdwn
index e6c6085d..0b53578a 100644
--- a/assignment8.mdwn
+++ b/assignment8.mdwn
@@ -8,15 +8,17 @@
 
 		let rec move_botleft (z : 'a zipper) : 'a zipper =
 			(* returns z if the targetted node in z has no children *)
-			(* else returns move_botleft (zipper which results from moving down and left in z) *)
-			YOU SUPPLY THE DEFINITION
+			(* else returns move_botleft (zipper which results from moving down from z to the leftmost child) *)
+			_____
+			(* YOU SUPPLY THE DEFINITION *)
 
 
 		let rec move_right_or_up (z : 'a zipper) : 'a zipper option =
 			(* if it's possible to move right in z, returns Some (the result of doing so) *)
 			(* else if it's not possible to move any further up in z, returns None *)
 			(* else returns move_right_or_up (result of moving up in z) *)
-			YOU SUPPLY THE DEFINITION
+			_____
+			(* YOU SUPPLY THE DEFINITION *)
 
 
 		let new_zipper (t : 'a tree) : 'a zipper =
@@ -129,28 +131,3 @@
 		(same-fringe? tree1 tree2)
 
 
-<!--
-		(define (lazy-flatten tree)
-		  (letrec ([helper (lambda (tree tailk)
-		                  (cond
-		                    [(pair? tree)
-		                      (helper (car tree) (lambda () (helper (cdr tree) tailk)))]
-		                    [else (cons tree tailk)]))])
-		    (helper tree (lambda () (list)))))
-		
-		(define (stream-equal? stream1 stream2)
-		  (cond
-		    [(and (null? stream1) (null? stream2)) #t]
-		    [(and (pair? stream1) (pair? stream2))
-		     (and (equal? (car stream1) (car stream2))
-		          (stream-equal? ((cdr stream1)) ((cdr stream2))))]
-		    [else #f]))
-		
-		(define (same-fringe? tree1 tree2)
-		  (stream-equal? (lazy-flatten tree1) (lazy-flatten tree2)))
-		
-		(define tree1 '(((1 . 2) . (3 . 4)) . (5 . 6)))
-		(define tree2 '(1 . (((2 . 3) . (4 . 5)) . 6)))
-		
-		(same-fringe? tree1 tree2)
--->