Changeset 3218

Timestamp:

05/30/08 13:37:11 (7 months ago)

Author:

ksprotte

Message:

branches/bos-trunk-sat: added a simple queue implementation

Files:

• branches/bos-trunk-sat/projects/bos/web/utils.lisp (modified) (1 diff)

branches/bos-trunk-sat/projects/bos/web/utils.lisp

@@ -440 +440 @@
-        do (vector-push-extend c result)
-        finally (return result)))
+
+;;; simple queue
+(defun make-queue ()
+  (cons nil nil))
+
+(defun queue-empty-p (queue)
+  (null (car queue)))
+
+(defun enqueue (x queue)
+  (if (null (car queue))
+      (setf (cdr queue) (setf (car queue) (list x)))
+    (setf (cdr (cdr queue)) (list x)
+          (cdr queue) (cdr (cdr queue))))
+  (car queue))
+
+(defun dequeue (queue)
+  (pop (car queue)))
+