画pl线小程序。请问如何象pl命令那样可以在画的过程中使用undo撤消。
(defun c:gpl( / obj1 obj2 gp1 gp2) (setq obj2 nil) (setq gp1 (getpoint)) (while (setq gp2 (getpoint gp1)) (command "pline" gp1 gp2 "" ) (setq obj1 (entlast)) (if ( /= obj2 nil) (command "pedit" "m" obj1 obj2 "" "j" "j" "b" 1 "") ) (setq obj1 (entlast) gp1 gp2 obj2 obj1 ) );while );defun |