[Python-Dev] Re: Dynamic nested scopes

[Barry A. Warsaw]

>>>>> "GvR" == Guido van Rossum <guido@python.org> writes:

    GvR> The built-in names have always been part of the language
    GvR> definition in my mind.  The way they are implemented doesn't
    GvR> reflect this, but that's just an implementation detail.  How
    GvR> would you like it if something claimed to be Python but
    GvR> didn't support len()?  Or map()?

    GvR> That doesn't mean you can't add new built-ins, and I don't
    GvR> think that the new implementation will prevent that -- but it
    GvR> *will* assume that you don't mess with the definitions of the
    GvR> existing built-ins.

    GvR> Of course you still will be able to define functions whose
    GvR> name overrides a built-in -- in that case the compiler can
    GvR> see that you're doing that (because it knows the scope rules
    GvR> and can see what you are doing).  But you won't be able to
    GvR> confuse someone else's module by secretly sticking a
    GvR> replacement built-in into their module's __dict__.

I'm a little confused.  I've occasionally done the following within an
application:

----------driver.py
# need to override built-in open() to do extra debugging
def debuggin_open(filename, mode, bufsize):
    # ...
if EXTRA_DEBUGGING:
    import __builtin__.__dict__['open'] = debugging_open
-------------------- snip snip --------------------

Would this be illegal?  Would other modules in my application (even if
imported from the standard library!) automatically get
debugging_open() for open() like they do now?

-Barry