1 files changed, 33 insertions, 0 deletions
diff --git a/list.csc b/list.csc
new file mode 100644
index 0000000..c4bc013
--- /dev/null
+++ b/list.csc
@@ -0,0 +1,33 @@
+(define-library (csc list)
+  (export
+    revappend
+    split-at
+    take)
+  (import (scheme base))
+  (begin
+
+
+    (define (take n xs)
+      (let loop ((n n)
+                 (xs xs)
+                 (acc '()))
+        (if (or (not (positive? n)) (null? xs))
+            (reverse acc)
+          (loop (- n 1) (cdr xs) (cons (car xs) acc)))))
+
+
+    (define (split-at n xs)
+      (let loop ((n n)
+                 (xs xs)
+                 (acc '()))
+        (if (or (not (positive? n)) (null? xs))
+            (values (reverse acc) xs)
+          (loop (- n 1) (cdr xs) (cons (car xs) acc)))))
+
+
+    (define (revappend a b)
+      (let loop ((xs a)
+                 (acc b))
+        (if (null? xs)
+            acc
+          (loop (cdr xs) (cons (car xs) acc)))))))