+(defun agentset-list (agentset)
+ (cond
+ ((eql agentset :turtles) *turtles*)
+ ((eql agentset :patches) *patches*)
+ ((and (listp agentset) (eql :agentset (car agentset))) (cddr agentset))
+ (t (error "Doesn't seem to be an agentset: ~A" agentset))))
+
+(defun agentset-breed (agentset)
+ (cond
+ ((eql agentset :turtles) :turtles)
+ ((eql agentset :patches) :patches)
+ ((and (listp agentset) (eql :agentset (car agentset))) (second agentset))
+ (t (error "Doesn't seem to be an agentset: ~A" agentset))))
+
+(defun list->agentset (list breed)
+ (append (list :agentset breed) list))
+
+(defun agentset-p (o)
+ (or
+ (eql o :turtles)
+ (eql o :patches)
+ (and (listp o) (eql :agentset (car o)))))
+
+(defun agent-p (o)
+ (or (turtle-p o) (patch-p o)))
+
+(defun breed-p (breed)
+ (find breed *breeds* :key #'car))
+
+(defun breed-default-shape (breed)
+ (second (find breed *breeds* :key #'car)))
+
+(defsetf breed-default-shape (breed) (shape)
+ `(setf (second (find ,breed *breeds* :key #'car)) ,shape))