Multiple versions of Python coexisting in the same OS

[Edward Diener]

On 7/25/2010 5:57 PM, Thomas Jollans wrote:
> On 07/25/2010 11:10 PM, Edward Diener wrote:
>> On 7/25/2010 3:39 PM, Christian Heimes wrote:
>>> Am 25.07.2010 21:32, schrieb Thomas Jollans:
>>>> If a script uses sys.executable instead of "python", there is no
>>>> problem, at all.
>>>
>>> It's true that sys.executable is the best way if you have to start a new
>>> Python interpreter. However sys.executable may not be set for NT
>>> services. So there may be a problem after all.
>>>
>>
>> Once you start instrusively changing scripts to find a solution to
>> multiple versions of Python co-existing in one system, you are heading
>> down a path of endless problems.
>
> What exactly is it that you're afraid to change?

I do not want to intrusively change any script that has been installed 
as part of Python. I shouldn't even have to know about the code in these 
scripts other than what good documentation tells me in how to use them.

That's not to say having source is worthless. I am just not going to 
change source to get a version of Python to work properly when I have 2 
or more versions installed in their own separate folders.

>
> The standard library? There's certainly no need to change that in any way!

So if a standard library module ( or distributed library ) executes a 
call internally to 'python xxx yyy' or executes a call internally to 
'someScript.py yyy', you're fine with multiple co-existing versions of 
Python on your system ?

Because under Windows the first call will look for the python.exe first 
found in the PATH while the second call will find the python.exe 
associated with the .py extension. And it does not matter in either case 
what version of the multiple installed versions of Python which are on 
my system is currently executing that script.

And please don't say that there is some sort of guarantee that no 
library or installation would invoke Python in such a way as opposed to 
the normal 'import AScript.py' method of using functionality in Python 
scripts.