+(defmacro defagent-value (type symb &optional accessor)
+ (let
+ ((accessor (or accessor (intern (format nil "~A-~A" type symb))))
+ (agent (gensym))
+ (var (gensym))
+ (new-val (gensym)))
+ `(progn
+ (defmethod agent-value-inner ((,agent ,type) (,var (eql ,symb))) (,accessor ,agent))
+ (defmethod set-agent-value-inner ((,agent ,type) (,var (eql ,symb)) ,new-val) (setf (,accessor ,agent) ,new-val)))))
+
+; Don't want the setter for :who
+(defmethod agent-value-inner ((turtle turtle) (var (eql :who))) (turtle-who turtle))
+
+(defagent-value patch :pcolor patch-color)
+
+(defagent-value turtle :color)
+(defagent-value turtle :label)
+(defagent-value turtle :label-color)
+(defagent-value turtle :size)
+
+(defmethod agent-value-inner ((turtle turtle) var)
+ (when (not (find var *turtles-own-vars*)) (error "~S is not a turtle variable" var))
+ (or (getf (turtle-own-vars turtle) var) 0d0))
+
+(defmethod set-agent-value-inner ((turtle turtle) var new-val)
+ (when (not (find var *turtles-own-vars*)) (error "~S is not a turtle variable" var))
+ (if (getf (turtle-own-vars turtle) var)
+ (setf (getf (turtle-own-vars turtle) var) new-val)
+ (setf (turtle-own-vars turtle) (append (list var new-val) (turtle-own-vars turtle)))))
+
+(defmethod agent-value-inner ((patch patch) var)
+ (when (not (find var *patches-own-vars*)) (error "~S is not a patch variable" var))
+ (or (getf (patch-own-vars patch) var) 0d0))
+
+(defmethod set-agent-value-inner ((patch patch) var new-val)
+ (when (not (find var *patches-own-vars*)) (error "~S is not a patch variable" var))
+ (if (getf (patch-own-vars patch) var)
+ (setf (getf (patch-own-vars patch) var) new-val)
+ (setf (patch-own-vars patch) (append (list var new-val) (patch-own-vars patch)))))