[Python-Dev] Add a -z interpreter flag to execute a zip file

[Phillip J. Eby]

At 10:53 PM 7/12/2007 +0200, Martin v. Löwis wrote:
> > The approach is cross-platform, in that you can use the approach on
> > different platforms. The result of the approach, however, is not
> > cross-platform. You can't distribute your single zip-as-executable to
> > both Windows and bourne-shell-using platforms. The -z argument does
> > allow that.
>
>I still don't understand how so. How will this work on Windows?

Via the .pyz extension on Windows, and a shebang header everywhere 
else... although the path and possibly Python version will have to be 
hardcoded in the shebang line.


> > The -z argument makes it extremely simple: the user decides which python
> > to run, and the program is run directly just like it would if it was
> > unpacked and run that way.
>
>Really? I think there a still a number of subtleties, like what
>sys.argv[0] will be, and how sys.path will look like. It's definitely
>*not* the same as if you unzipped it, and ran the unzipped one.

IMO, sys.argv[0] should equal the -z argument, as should the "script 
directory" entry on sys.path.

Actually, the more I think about this, the more I'm leaning towards 
getting rid of the option and just having the startup code check 
whether sys.argv[0] can be mapped to an importer object, and if so, 
importing __main__ from it.  A special "python script file" importer 
type could be implemented for file objects, so that importing 
__main__ from it will execute the contents of the file in a __main__ module.

This approach would provide uniform argv[0] handling (in that "python 
argv[0]" will always rerun the same program) and allow zipfile 
shebangs to use 'env' to invoke Python, since no command-line option 
is then required.

There is one slight complication: the "python script file" importer 
must adjust sys.path[0] to the directory of the script, instead of 
the script itself.