[Python-Dev] Python launcher command line usage (Was: 3.2.1 encoding surprise)

[Mark Hammond]

On 20/07/2011 1:00 AM, Paul Moore wrote:
> On 19 July 2011 02:41, Vinay Sajip<vinay_sajip at yahoo.co.uk>  wrote:
>> The use of py from the command line is merely a convenience for developers (as
>> the PEP says) - it's better to rely on shebang lines together with settings in
>> the .ini to get the behaviour you want.
>
> But it's a *huge* convenience for running multiple Python versions,
> particularly as no existing Python versions install executables with
> the version in the name (python3.exe, python3.2.exe, etc).And BAT
> files aren't a suitable option (I'll rant about the issues with BAT
> files if you want, but I recommend you don't ask :-))
>
> Being able to say py -3, py -2.7, etc, rather than having to hack
> PATH, create renamed copies of exes, etc, is arguably more of a
> benefit to me than shebang support.

Ditto for me.

> This may explain why I'd like to see a command-line means of invoking
> custom commands. Something like py.exe looking at an initial argument,
> and if it's of the form "-cmd" for a command in py.ini, then run that
> command, passing remaining arguments just as for py -3. (Maybe --cmd
> to match standard long option usage would be better?)
>
> Presumably, if this idea is to go anywhere, it would need adding to
> the PEP. Mark, do you think it would be useful?

I doubt I will find it useful - but I'm on record as saying I wont find 
the custom command support itself useful :)  But similarly with that 
support, evidence that enough people *will* find it useful is enough for 
me to support the concept.

My current thinking re the PEP is to make it much smaller - just 
describe the concepts and try to avoid as much implementation detail as 
possible - I see no reason the PEP needs to take a stance on issues like 
that - this feature really could be treated just like any other feature 
request in Python - a loose consensus and acceptable patch is all that 
is needed.

Mark