(defvar *current-id* 0)
(defvar *turtles* nil)
+(defvar *turtles-own-vars* nil)
+(defvar *patches-own-vars* nil)
(defvar *patches* nil)
(defvar *myself* nil)
(defvar *self* nil)
(defvar *dimensions* nil)
+(defvar *globals* nil)
(defvar *topology* :torus)
(defvar *ticks* nil)
(defvar *breeds* nil)
-(defstruct turtle who color heading xcor ycor (label "") (label-color 9.9d0) (size 1d0) shape)
-(defstruct patch color xcor ycor)
+(define-condition stop nil nil)
+
+(defmacro with-stop-handler (&rest forms)
+ "MACRO WITH-STOP-HANDLER &rest FORMS => HANDLED-FORM
+
+ARGUMENTS AND VALUES:
+
+ FORMS: body to be handled
+ HANDLED-FORM: body with handling
+
+DESCRIPTION:
+
+ WITH-STOP-HANDLER is a convenience macro to handle when
+ programs issue a stop condition. When one does, a simple
+ :stop is returned."
+ `(handler-case (progn ,@forms) (stop (s) (declare (ignore s)) :stop)))
+
+(defstruct turtle who color heading xcor ycor (label "") (label-color 9.9d0) (size 1d0) shape own-vars)
+(defstruct patch color xcor ycor own-vars turtles)
(defun agentset-list (agentset)
(cond