from turtle import *

# setup(width=1.0, height=1.0) # same crash either way
title("Experiment with Key Presses")
setundobuffer(None) # same crash either way

shape('turtle')
vel = 5 # pixels per press or repeat

def krt(): seth(  0); fd(vel)
def kup(): seth( 90); fd(vel)
def klt(): seth(180); fd(vel)
def kdn(): seth(270); fd(vel)

onkeypress(krt,'Right')
onkeypress(kup,'Up')
onkeypress(klt,'Left')
onkeypress(kdn,'Down')

listen()

def gobye(x,y): bye()
onscreenclick(gobye, 3) # exit with right click as well as close button

mainloop()

# Winxp, IDLE editor, F5-run: works and quits, but if move about 1000 times
# MS VC++ Runtime Library runtime error pythonw.exe asked runtime to exit...
# [click] pythonw has encounter error....
# and in IDLE shell window see following (multiple, first before crash)
'''
Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Programs\Python31\lib\tkinter\__init__.py", line 1399, in __call__
    return self.func(*args)
  File "C:\Programs\Python31\lib\turtle.py", line 701, in eventfun
    fun()
  File "C:/Programs/Python31/turt/key.py", line 22, in kup
    def kup(): seth( 90); fd(vel)
  File "<string>", line 1, in seth
  File "C:\Programs\Python31\lib\turtle.py", line 1933, in setheading
    self._rotate(angle)
  File "C:\Programs\Python31\lib\turtle.py", line 3274, in _rotate
    self._update()
  File "C:\Programs\Python31\lib\turtle.py", line 2657, in _update
    self._update_data()
  File "C:\Programs\Python31\lib\turtle.py", line 2648, in _update_data
    self._pencolor, self._pensize)
  File "C:\Programs\Python31\lib\turtle.py", line 547, in _drawline
    self.cv.itemconfigure(lineitem, fill=fill)
  File "<string>", line 1, in itemconfigure
  File "C:\Programs\Python31\lib\tkinter\__init__.py", line 2229, in itemconfigure
    return self._configure(('itemconfigure', tagOrId), cnf, kw)
  File "C:\Programs\Python31\lib\tkinter\__init__.py", line 1171, in _configure
    cnf = _cnfmerge((cnf, kw))
  File "C:\Programs\Python31\lib\tkinter\__init__.py", line 68, in _cnfmerge
    if isinstance(cnfs, dict):
RuntimeError: maximum recursion depth exceeded while calling a Python object
'''