On 03/05/2011 06:33 PM, Nick Coghlan wrote:
On Sun, Mar 6, 2011 at 4:11 AM, Ron Adam<r...@ronadam.com> wrote:
Adding a second references to the '__main__' module begins to blur the
purpose of sys.modules from being a place to keep imported modules to a
place that also has some ordering information. (Practicality over purity?,
Or an indication of what direction to go in?)
And, if you ask for keys, items, or values, you will need to filter out
'__main__' to avoid the double reference.
So I was thinking, what if we make sys.modules a little smarter. The
negative of that is, it would no longer be a simple dictionary object.
First idea ...
Add a __main__ attribute to sys.modules to hold the name of the main module.
Override modules.__setitem__, so it will catch '__main__' and set
modules.__main__ to the name of the module, and put the module in under its
real name instead of '__main__'.
Override modules.__getitem__, so it will catch '__main__' and return
self[self.__main__].
Then keys(), values(), and items(), will not have the doubled main module
references in them.
The name of the main module is easy to get. ie... sys.modules.__main__
sys.modules[__name__] will still return the correct module if __name__ ==
"__main__".
That's quite an interesting idea - I hadn't even considered the
implications of double counting the affected module when iterating
over sys.modules in some fashion. That said, dropping `__main__` from
the iteration might confuse existing code, so it may be better to have
the lookup go the other way (i.e. define __missing__ on the dict
subclass and return sys.modules['__main__'] if the key matches
sys.modules.__main__).
... if the key matches sys.modules.__missing__
Works for me. ;-)
We can find a better name than __missing__ later. (minor detail)
Cheers,
Ron
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