[Python-Dev] New update to PEP397 - Python launcher for Windows

[Glenn Linderman]

On 7/20/2011 11:35 PM, Mark Hammond wrote:
> Virtual commands in shebang lines:
>
>      Virtual Commands are shebang lines which start with strings which would
>      be expected to work on Unix platforms - examples include
>      '/usr/bin/python', '/usr/bin/env python' and 'python'.  Optionally, the
>      virtual command may be suffixed with a version qualifier (see below),
>      such as '/usr/bin/python2' or '/usr/bin/python3.2'.  The command executed
>      is based on the rules described in Python Version Qualifiers below.

I note in passing that '/usr/bin/env python' is hard-coded in the 
launcher, which conforms to the above documentation.  But there is no 
hard requirement in Unix, if I correctly understand it, that 
'/usr/bin/env' be separated from 'python' (or whatever) by exactly one 
space.  While I doubt it is frequently used with other than a single 
space, I think it would be legal to have 2 or 3 or 10 spaces, and maybe 
even tabs or a mixture, and it would work on Unix... but not in the 
launcher.

It would somewhat complicate the launcher code to have an additional 
case to check for /usr/bin/env, skip following white space, and then 
compare to python, but it would be more robust.

If it is thought that hard-coding a single space covers most of the 
uses, it should at least be emphasized in the documentation that only 
commands of than nature containing a single space will work with the 
launcher.

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