PEP: import version

[Manlio Perillo]

Hi.
I'm a new user of Python but I have noted a little problem.
Python is a very  good language but it is evolving, in particular its
library is evolving.
This can be a problem when, ad example, a module change its interface
or its implementation in a fundamental way (an example: wxPython).
This, I think, can be resolved by allowing an user to explicitly say
what  version of a module it wants (sush as version numbers in Linux
shared objects).

A possible syntax is this:
import wxPython version '2.4'

When the version number is missing, the latest version is loaded.

The syntax of the version number can be expanded.
Ad example, when a module change totally its interface, instead of
renaming it, one can be do (its only an example):
import mymodule version '0'

Another case is when the module is implemented also in C:
import picke version 'C'


This new syntax can be implemented by using version numbers on the
module file name, or by introducing a new special variable at module
level: __moduleversion__

A module implementator can check against this variable:

def foo():
	if __moduleversion__ < 2:
		# compatibility
		pass
	else:
		return something

(It would be better if the check can be done at module loading time)


Regards   Manlio Perillo