On Mon, Feb 5, 2018 at 6:04 AM, Paul Moore
On 5 February 2018 at 08:10, Steve Barnes
wrote: When a new version of python is in alpha/beta it is often desirable to have it installed for tests but remain on a previous version for day to day use.
However, currently the Windows py launcher defaults to the highest version that it finds, which means that unless you are very careful you will end up having to explicitly specify your older version every time that you start python with it once you have installed the newer version.
I an thinking that it would be relatively simple to expand the current launcher functionality to allow the user to set the default version to be used.
One possible syntax, echoing the way that versions are displayed with the -0 option would be to allow py -n.m* to set and store, either in the registry, environment variable or a configuration file, the desired default to be invoked by py or pyw.
Personally I thing that this would encourage more people to undertake testing of new candidate releases of python.
I would be interested in any feedback on the value that this might add.
There's a `py.ini` file that lets you set the default version. See https://docs.python.org/3.6/using/windows.html#customization for details. Is that just something you weren't aware of, or does it not address the issue you're having?
I think the feature is still worth considering. Playing with .ini files should be considered a hack, while a way to change the default may be useful for many, at all skill levels. In your link, though, the recommended way to change the default is to use the environment variable %PY_PYTHON%, rather than the .ini file. But environment variables are not as key to Windows use as it is to Linux use, so the feature is still worth considering. Does the installer offer to change the default to its version, even when running it after installation? If it does, it still might be good to add an option to py.exe, because it's closest to where you'd think to want to change the setting.