Checkpoint before unquote-splicing

bin/pre.slime.expanded

@@ -1,3 +1,5 @@
+(show do-list)
+
 (define (nil? x) "Checks if the argument is nil." (= x nil))
 
 (define (number? x) "Checks if the argument is a number." (= (type x) :number))
@@ -26,8 +28,11 @@ ithe sequence as arguemens." (eval (pair fun seq)))
 (define (extend seq elem) "Extends a list with the given element, by putting it in
 the (rest) of the last element of the sequence." (if (pair? seq) (begin (define e (end seq)) (mutate e (pair (first e) elem)) seq) elem))
 
+(define (extend2 seq elem) "Extends a list with the given element, by putting it in
+the (rest) of the last element of the sequence." (printf "addr of (end seq)" (addr-of (end seq))) (if (pair? seq) ((lambda (e) (begin (printf "addr if e inner" (addr-of e)) (mutate e (pair (first e) elem)) seq)) (end seq))) elem)
+
 (define (append seq elem) "Appends an element to a sequence, by extendeing the list
-with (pair elem nil)." (extend seq (pair elem nil)))
+with (pair elem nil)." (extend seq (pair elem ())))
 
 (define (length seq) "Returns the length of the given sequence." (if (nil? seq) 0 (+ 1 (length (rest seq)))))
 
@@ -61,7 +66,9 @@ function to every value in the sequence. If the result of that
 funciton application returns a truthy value, the original value is
 added to a list, which in the end is returned." (if seq ([C-function] (if (fun (first seq)) (pair (first seq) (filter fun (rest seq))) (filter fun (rest seq)))) nil))
 
-(define (zip l1 l2) (if (and (nil? l1) (nil? l2)) nil (pair (list (first l1) (first l2)) (zip (rest l1) (rest l2)))))
+(define (zip l1 l2) (if (and (nil? l1) (nil? l2)) nil ([C-function] (pair (list (first l1) (first l2)) (zip (rest l1) (rest l2))))))
+
+(define (unzip lists) (if lists ([C-function] (define (iter lists l1 l2) (define elem (first lists)) (if elem (iter (rest lists) (pair (first elem) l1) (pair (first (rest elem)) l2)) (list l1 l2)))) nil) (iter lists () ()))
 
 (define (enumerate seq) (define (enumerate-inner seq next-num) (if seq ([C-function] (pair (list (first seq) next-num) (enumerate-inner (rest seq) (+ 1 next-num)))) nil)) (enumerate-inner seq 0))