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| -rw-r--r-- | utilities.lisp | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/utilities.lisp b/utilities.lisp index 214189f..69ddcfe 100644 --- a/utilities.lisp +++ b/utilities.lisp @@ -55,3 +55,11 @@ (setf (nth n list) (nth m list) (nth m list) tmp) list)) + +(defun pop-nth (n list &optional share-tail) + (when (minusp n) + (setf n (+ n (length list)))) + (multiple-value-bind (front back) (take n list share-tail) + (values + (nconc front (cdr back)) + (car back)))) |