help:problem using the RawPen class/turtle module.

[alex]

> 
> Hi, 
> thank you for your reply,
> 
> I tryied to type your code on my python command line
> and unfortunatly I have the same message.
> So well yes I think you are right, something's wrong
> in my configuration.
> 
> It seems that it comes from the turtle.py module, I'll
> try to have a look at it(even if I'm not an expert of
> python modules), 
> it seems strange to me that it doesn't work because 
> it is in the standard distribution and of course I 
> haven't changed it.
> 
> I made a copy & paste of my little test.
> 
> 
> Python 2.2 (#1, Mar  9 2002, 18:21:48) 
> [GCC 2.95.2 19991024 (release)] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
> >>> import turtle
> >>> import Tkinter
> >>> root=Tkinter.Tk()
> >>> c=Tkinter.Canvas(root)
> >>> c.pack(expand=1)
> >>> mypen=turtle.RawPen(c)
> Traceback (most recent call last):
>   File "<stdin>", line 1, in ?
>   File "/usr/local/lib/python2.2/lib-tk/turtle.py", line 16, in __init__
>     self.reset()
>   File "/usr/local/lib/python2.2/lib-tk/turtle.py", line 42, in reset
>     self.clear()
>   File "/usr/local/lib/python2.2/lib-tk/turtle.py", line 53, in clear
>     self._draw_turtle()
>   File "/usr/local/lib/python2.2/lib-tk/turtle.py", line 262, in _draw_turtle
>     self._arrow = _canvas.create_line(x-dx,y+dy,x,y,
> AttributeError: 'NoneType' object has no attribute 'create_line'
> 
> 
> alex.

I think I've found the problem,
it seems that the call to 

...
self._arrow = _canvas.create_line(x-dx,y+dy,x,y,
                                  width=self._width,
                                  arrow="last",
                                  capstyle="round",
                                  fill=self._color)

...

in the turtle.py ( _draw_turtle() method)
doesn't work because the _canvas to refer to is
the one in the 'self' instance,  
so with the following change:

self._arrow = self._canvas.create_line(x-dx,y+dy,x,y,....
              ^^^^^

everything is ok.

Without it the _canvas refers to a global that it
isn't been initialized to a Canvas when there is a
call to the RawPen class.

ale><