> It didn't form 2.5 to 2.6 (at least not intentionally). But with the > indroduction of the TurtleScreen class and the Screen class/object > (singleton) a few of the turtle methods were also implemented as screen > methods and as turtle methods declared deprecated (see docs of Python > 2.6). These deprecated turtle methods do not occur as turtle methods any > more in Python 3.x.
More info. Yes, there is no tracer attribute...when the object is created. But watch this (Python 3.1): >>> import turtle >>> tooter = turtle.Turtle() >>> tooter.tracer Traceback (most recent call last): File "<pyshell#2>", line 1, in <module> tooter.tracer AttributeError: 'Turtle' object has no attribute 'tracer' >>> tooter.hideturtle() >>> tooter.speed('fast') >>> turtle.update() >>> turtle.tracer <function tracer at 0x013E0ED0> Now, after setting hide, speed, update, a tracer exists. Is that supposed to happen? That explains why there was no error when I set the turtle attribute instead of the screen attribute. And, of course, setting the turtle attribute accomplishes nothing, as actual tracing is controlled by the screen attribute as you say. > > Among them is the tracer method, which in fact does not control single > turtle objects but all the turtles on a given screen. > > So there is an icompatibility beween 2.6 and 3.x > > But as far as I have understood, this doesn't concern the problem > reported by mensator. Only that the problem is hidden when tracing is off, as the nhops variable is never evaluated when trace is off. > > Regards, > Gregor -- http://mail.python.org/mailman/listinfo/python-list