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[Python-ideas] PEP for executing a module in a package containing relative imports

Brett Cannon brett at python.org
Sun Apr 22 20:39:01 CEST 2007 
On 4/22/07, Jim Jewett <jimjjewett at gmail.com> wrote:
> On 4/21/07, Brett Cannon <brett at python.org> wrote:
> > On 4/21/07, Josiah Carlson <jcarlson at uci.edu> wrote:
>
> > > After reading other posts in the thread, I'm going to put my support
> > > into the sys.main variant.  It has all of the benefits of the builtin __name__
> > > == __main__, with none of the drawbacks (no builtin!), and only a slight
> > > annoyance of 'import sys', which is more or less free.
>
> > Yeah, I am starting to like it as well.  Steven and Jim, what do you think?
>
> Better than adding a builtin.
>
> I'm not sure I like the idea of another semi-random object in sys
> either, though.
>
> (1)  One of the motivations was importing.  It looks like __file__
> already has sufficient information.  I understand that relying on it
> (or on __package__?) seems a bit hacky, but is it really worse than
> adding something?
>

Yes, because you have no guarantee __file__ will in any way be unique
or even defined (look at 'sys').  It's up to the loader to set
__file__ and it can do whatever it wants.  This doesn't happen with
__name__ since it is rather clear what that should be no matter where
the module was loaded from (unless it was a Python file specified at
the command line in some random directory).

-Brett
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