[Tutor] Configuration?

[Jeff Shannon]

Sison, Nick wrote:

>When running the GUI test session I get this right after I hit the exit
>button then python dies:
>
>When using IDLE I get this:  [...]
>
>When using PythonWin I get this:  [...]
>  
>

I believe this problem isn't anything that you've done wrong.  As it 
turns out, both IDLE and PythonWin have a similar weakness -- they both 
run scripts in the same process that they're running in, using the same 
Python interpreter.  This means that certain memory structures are 
shared between the IDE and any scripts that you're running in them. 
 Normally this is not a problem, but it does tend to cause issues when 
the scripts you're running use a GUI.  Different GUI toolkits tend to 
clash in ugly ways (thus PythonWin won't cooperate with Tkinter), and 
even with the same GUI toolkit (IDLE uses Tkinter as well) only one 
mainloop() is allowed per process, so trying to start a second 
mainloop() from within IDLE causes problems.

There's several ways around this problem.  The quickest is to simply 
launch your GUI app from a command prompt.  Open a command prompt window 
(and run DOSKey if you're using Win9x!), cd to the directory that your 
script is saved in, and run 'python myscript.py' -- your GUI should work 
much better.  You can make changes to the open window in IDLE/PythonWin, 
save the changes, and just hit the up-arrow and return in your command 
window to restart your script.

The other solution is to switch to a different IDE.  Sourceforge has a 
project called IDLEFork, which is an updated and upgraded version of 
IDLE.  (I think I've heard that IDLEFork will replace mainstream IDLE in 
the Python 2.3 distribution, but I'm not certain about that.)  One of 
the improvements in IDLEFork is that it runs scripts in their own 
process -- this means that you won't have the mainloop() clashes, and 
your GUI script should work just fine.  There's also a number of 
commercial IDEs (such as WingIDE and, I think, Komodo) that run Python 
scripts in a separate process, if you want to (and can afford to) go 
that route.

Hope this helps!

Jeff Shannon
Technician/Programmer
Credit International