+(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)))))
+
+(defagent-value turtle :who)
+
+(defagent-value patch :pcolor patch-color)