1 files changed, 26 insertions, 0 deletions

diff --git a/src/lisp/std.lisp b/src/lisp/std.lisp
new file mode 100644
index 0000000..c723a13
--- /dev/null
+++ b/src/lisp/std.lisp
@@ -0,0 +1,26 @@
+(define (caar ls) (car (car ls)))
+(define (caaar ls) (car (caar ls)))
+(define (caaaar ls) (car (caaar ls)))
+(define (caaaaar ls) (car (caaaar ls)))
+
+(define (cddr ls) (cdr (cdr ls)))
+(define (cdddr ls) (cdr (cddr ls)))
+(define (cddddr ls) (cdr (cdddr ls)))
+(define (cdddddr ls) (cdr (cddddr ls)))
+
+(define (null? ls) (eq? ls '()))
+
+(define (length ls)
+  (if (null? ls)
+    0
+    (+ 1 (length (cdr ls)))))
+
+(define (fold init accumulator ls)
+  (if (null? ls)
+    init
+    (fold (accumulator init (car ls))
+          accumulator
+          (cdr ls))))
+
+(define (sum ls) (fold 0 + ls))
+(define (product ls) (fold 1 * ls))