avoid non tail recursive function

1 files changed, 4 insertions, 3 deletions

diff --git a/core/util.lisp b/core/util.lisp
index 2814fae..ac4d528 100644
--- a/core/util.lisp
+++ b/core/util.lisp
@@ -20,9 +20,10 @@
   (remove-if (constantly t) sequence :start n :count 1))
 (declaim (ftype (function (list t unsigned-byte) list)))
 (defun insert (list value n)
-  (if (<= n 0)
-      (cons value list)
-      (cons (car list) (insert (cdr list) value (- n 1)))))
+  (if (= n 0)
+      (push value list)
+      (push value (cdr (nthcdr (1- n) list))))
+  list)
 (define-modify-macro insertf (value n) insert)
 (declaim (inline substitute/swapped-arguments remove-if/swapped-arguments))
 (defun substitute/swapped-arguments (sequence new old &rest keyword-arguments)