[Python-ideas] Make py.exe default to Python 3

[Andrew Barnert]

On Mar 17, 2016, at 01:10, Stephen J. Turnbull <stephen at xemacs.org> wrote:
> 
> And the language-level backward-compatibility burden is entirely borne
> by Microsoft -- which they are quite good at AFAICT, and that
> (expensive!) backward-compatibility is why "nobody [aka "Andrew
> Barnert"<wink/>] *ever*[sic] runs multiple versions of Word."

I wasn't running Word 2003 and Word 2007 as VBA development platforms, or using them side by side because I wanted both.[1] That's just what the installer decided to do.[2]

Most people don't notice this, because how many users launch Word from the command line or via Win-R?[3] Not to mention that most people don't keep upgrading the same Windows box continuously over Office's 4-year dev cycle;[4] they're either still running 2003, or they threw that laptop away long ago.

At any rate, the point is that Word is a terrible example of "everybody expects side-by-side installs but the latest-installed version wins"--most people don't expect side-by-side installs, and when you do get them, the latest version installed doesn't win (and, even if it did, they wouldn't notice). That doesn't necessarily mean it would be the wrong decision for Python, just that the argument "everyone else does it" doesn't help, because it's not true.

If we want to talk about language-level compatibility, Visual Studio might be a better example than Office. And, as mentioned earlier in the thread, Visual Studio solves this problem by putting a "switching script" on the PATH, which adds the selected copy's executables to the PATH when run (and by adding special start menu shortcuts to open a new command prompt with the PATH set up). So, CL.EXE doesn't come from the latest MSVS installed either.


  [1]: In fact, the only reason I needed Word 2007 in the first place was that i contracted for a company that insisted I have it, even though every document they sent me worked just fine in OpenOffice...

  [2]: This is just a guess, but I'd bet it's because the $100 Office Home Professional 2007 didn't include the same subset of apps as the $100 Office Personal Business 2003 it replaced, and they didn't want people complaining about the upgrade taking away their PowerPoint or Access or Publisher or whatever the way people complained during the 2000-2003 upgrade. You'd think they could solve that by just offering the same set of packages of apps under consistent names and price points so this never came up, and I'll bet every 4 years, the suite-integration dev team for Office thinks they've convinced management that's a good idea, and then 3 months before release they discover that marketing convinced PM otherwise, and they now have to deal with it.

  [3]: People _do_ launch it via Win search for "word" nowadays, but that uses Windows' clever search guessing and learning, not anything configurable by the installer or the user, unlike Win-R "winword".

  [4]: Or, if they do, either it's an IT-managed upgrade, or they're installing a pirated copy of the full Office suite (which probably has a custom installer?).