[Python-Dev] IDLE local scope cleanup
Guido van Rossum
Wed, 13 Nov 2002 15:42:08 -0500
> Here is my real problem. I used to just pass a regular dictionary to
> code.InteractiveInterpreter, which worked well enough. But I just
> discovered an issue with pickling in the PyCrust shell, illustrated
> Welcome To PyCrust 0.8 - The Flakiest Python Shell
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> Python 2.2.2 (#1, Oct 28 2002, 17:22:19)
> [GCC 3.2 (Mandrake Linux 9.0 3.2-1mdk)] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
> >>> import pickle
> >>> def foo():
> ... pass
> >>> pickle.dumps(foo)
> Traceback (most recent call last):
> File "<input>", line 1, in ?
> File "/usr/local/lib/python2.2/pickle.py", line 978, in dumps
> Pickler(file, bin).dump(object)
> File "/usr/local/lib/python2.2/pickle.py", line 115, in dump
> File "/usr/local/lib/python2.2/pickle.py", line 225, in save
> f(self, object)
> File "/usr/local/lib/python2.2/pickle.py", line 519, in save_global
> raise PicklingError(
> PicklingError: Can't pickle <function foo at 0x8654b9c>: it's not found
> as __main__.foo
> So I decided to switch to using sys.modules['__main__'].__dict__, which
> eliminated the pickling error, but introduced a bunch of clutter in the
> local namespace. Any suggestions?
Remove the clutter. This probably means having a very minimal "real"
main program. IDLE does this by putting all the real code in the
"run" module, and bootstrapping the subprocess as follows:
python -c "__import__('run').main()"
This is roughly equivalent to executing
except that it doesn't create a variable 'run'.
--Guido van Rossum (home page: http://www.python.org/~guido/)