[Python-Dev] Draft PEP and reference implementation of a Python launcher for Windows

[Terry Reedy]

On 3/20/2011 6:35 PM, Westley Martínez wrote:
> On Sun, 2011-03-20 at 05:36 -0400, Terry Reedy wrote:

>> As both a writer and reader, I would like to just add, for instance,
>>
>> #! python3
>>
>> (or 3.3 or whatever) and have the launcher do the 'right thing'.
>> It seems to me that that really should be enough info for *nix,
>> but given that it is not, a program to add the required extra noise  for
>> a particular distribution to the first line of every module in a package
>> should not be too difficult.
>>
>> The above would be easy for anyone to write and understand.
>>
> That would break the whole point of platform-independence.  UNIX won't
> understand that, and I don't think we're gonna be able to convince all
> the kernel developers to implement this simplified shebang.

Given that the default for code developed on windows is NO #! line (and 
that may also be true for new programmers in *nix too, for all I know), 
I should think that the above would be an improvement. It does not 
require new Python programmers on Windows to know anything about *nix 
(pseudo?)paths, nor about the '/' versus '\' fuss. One should only need 
to know all that if one wishes to distribute to *nix *and* to have 
script files directly executable. (I presume 'python x.py' does not 
require a #! line on *nix either.)

For people who do want to do that, I already suggested that there be a 
program that scans through a directory tree, looking for files that 
start with '#! " and replacing that when found with '#!/usr/bin/env ' or 
whatever. That could be done once, before distribution. And it would not 
even require understanding of the substitution.

-- 
Terry Jan Reedy