1 files changed, 15 insertions, 0 deletions

diff --git a/src/lisp/std.lisp b/src/lisp/std.lisp
index 6c5beed..a256125 100644
--- a/src/lisp/std.lisp
+++ b/src/lisp/std.lisp
@@ -40,6 +40,13 @@
       (cons (func (car ls))
             (map func (cdr ls)))))
 
+(define (zip l1 l2)
+  (if (or (null? l1)
+          (null? l2))
+      '()
+      (cons (cons (car l1) (car l2))
+            (zip (cdr l1) (cdr l2)))))
+
 (define (filter pred ls)
   (if (null? ls)
       '()
@@ -57,3 +64,11 @@
 
 (define (sum ls) (fold 0 + ls))
 (define (product ls) (fold 1 * ls))
+
+(define (reverse ls)
+  (begin
+    (define (rev-helper p acc)
+      (if (null? p)
+          acc
+          (rev-helper (cdr p) (cons (car p) acc))))
+    (rev-helper ls '())))