On Jan 3, 2008 8:05 AM, Tim Chase <[EMAIL PROTECTED]> wrote:
> >> But you can't alter the values for True/False globally with this.
> >
> > Are you sure ? what about the following example ?
> > Is this also shadowing ?
> >
> >>>> import __builtin__
> >>>> __builtin__.True = False
> >>>> __builtin__.True
> > False
>
> It doesn't seem to screw things up globally
>
> >>> import __builtin__
> >>> t = __builtin__.True
> >>> __builtin__.True = False
> >>> __builtin__.False = t
> >>> True
> False
> >>> False
> True
> >>> 1 == 1
> True
> >>> import os
> >>> os.path.isdir('.')
> True
> >>> #if they were globally redefined, this would be False
> >>> #you'd have to actually reference __builtin__.True
>
> My thought would be if you do something as daft as
> redefining/shadowing True and False, you get the headaches that
> ensue. Fortunately, since Python is explicit, you can trace back
> through the code and see where the inanity occurred.
> Additionally, any scoping rules mean that programmer stupidity
> can't leak too badly outside the scope of the block containing
> the stupidity.
>
> It's the old "DIHWIDT! WDDT!" ("Doctor, it hurts when I do
> this!", "well don't do that!") syndrome.
>
In Py3k this will be a syntax error, like assigning to None is now.
Possibly also in 2.6.
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