[Python-ideas] Windows temporary file association for Python files

[anatoly techtonik]

On Mon, Oct 22, 2012 at 4:16 PM, Mark Lawrence <breamoreboy at yahoo.co.uk>wrote:

> On 22/10/2012 13:42, anatoly techtonik wrote:
>
>> On Mon, Oct 22, 2012 at 2:44 PM, Paul Moore <p.f.moore at gmail.com> wrote:
>>
>>> On 22 October 2012 11:51, anatoly techtonik <techtonik at gmail.com> wrote:
>>>
>>>> I wonder if it will make the life easier if Python was installed with
>>>> .py association to "%PYTHON_HOME%\python.exe" "%1" %*
>>>> It will remove the need to run .py scripts in virtualenv with explicit
>>>> 'python' prefix.
>>>>
>>>
>>> In Python 3.3 and later, the "py.exe" launcher is installed, and this
>>> is the association for ".py" files by default. It looks at the #! line
>>> of .py files, so you can run a specific Python interpreter by giving
>>> its full path. You can also specify (for example) "python3" or
>>> "python3.2" to run a specific Python version.
>>>
>>
>> Yes, I've noticed that this nasty launcher gets in the way. So, do you
>> propose to edit source files every time I need to test them with a new
>> version of Python? My original user story:
>>
>
> I see nothing nasty in the launcher, rather it's extremely useful.  You
> don't have to edit your scripts.  Just use py -3.2, py -2 or whatever to
> run the script, the launcher will work out which version to run for you if
> you're not specific.


Nice. Didn't know about that.


>       I want to execute scripts in virtual environment (i.e. with Python
>> installed for this virtual environment) without 'python' prefix.
>>
>> Here is another one. Currently Sphinx doesn't install with Python 3.2
>> and with Python 3.3 [1]. Normally I'd create 3 environments to
>> troubleshoot it and I can not modify all Sphinx files to point to the
>> correct interpreter to just execute 'setup.py install'.
>>
>
> Please try running your scripts with the mechanism I've given above and
> report back what happens, hopefully success :)


Not really. It doesn't work with virtualenv at all.

E:\p>cat version.py
import sys
print(sys.version)
E:\p>python version.py
3.3.0 (v3.3.0:bd8afb90ebf2, Sep 29 2012, 10:55:48) [MSC v.1600 32 bit
(Intel)]

E:\p>32\Scripts\activate
(32) E:\p>python version.py
3.2.3 (default, Apr 11 2012, 07:15:24) [MSC v.1500 32 bit (Intel)]

(32) E:\p>version.py
2.7.3 (default, Apr 10 2012, 23:31:26) [MSC v.1500 32 bit (Intel)]

(32) E:\p>py version.py
2.7.3 (default, Apr 10 2012, 23:31:26) [MSC v.1500 32 bit (Intel)]


>
>> A solution would be to teach launcher to honor PYTHON_PATH variable if
>> it is set (please don't confuse it with PYTHONPATH which purpose is
>> still unclear on Windows).
>>
>
> What is PYTHON_PATH?  IIRC I was told years ago *NOT* to use PYTHONPATH on
> Windows so its purpose to me isn't unclear, it's completely baffling.
>

Sorry, it was PYTHON_HOME - variable from .py association I proposed, i.e.
"%PYTHON_HOME%\python.exe" "%1" %*
If association is made in this way, then virtualenv could override PYTHON_HOME
and get `version.py` command execute with it's own interpreter.

Now with py.exe it looks a better idea to have PYTHONBIN environment
variable and the association set to "%PYTHONBIN%" "%1" %*. This way
virtualenv can easily override it during activation to make .py files
executable with whatever Python (or PyPy) it has configured.
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