On 07/03/2011 22:48, Mark Hammond wrote:
On 8/03/2011 7:33 AM, Michael Foord wrote:
A python launcher as you describe is a *great* idea.
A few concerns:
* we're missing an opportunity to do something easy (Martin is happy to modify the installer and says it is easy) for something that may or may not happen
Don't let my -0 stop anyone :)
Will you be at PyCon this year?
* will you call it python.exe? will it be installed by the python installer?
- I doubt calling it python.exe will fly, but I'm not sure. If so what will you call what is currently 'python.exe'? - if not then "python foo.py" on the command line will *still* not work...
Calling it python.exe would make the most sense for people who don't look behind the curtain, but I agree it could potentially be confusing for people. Further, we would need to ensure we didn't create an infinite loop where the launcher python.exe found a python.exe it thought was an appropriate sub-process, but where it turns out it is actually another launcher.
Sounds like fun. :-)
Having it installed by the Python installer also makes sense to me but I'd be very interested in Martin's take on this (and also on everything else we are discussing here).
Ditto.
* we're (yet again) making instructions for running stuff on Windows *different* to other platforms (and making tutorials written for other pythons "not work" in certain ways)
Actually, I'd argue we are making them more similar as we would be honoring a shebang line and allowing the exact same mechanism be used to denote the major version of Python needed.
Well, except (as pointed out a few minutes ago) that *isn't* what unix does ("python foo.py" does not honour the shebang). It gets us to something that works reliably though so I still like the idea.
* as I work with multiple platforms it would be really nice if the same invocations worked across all of them - whilst I say again that I really like the idea of the launcher it doesn't conflict with the other suggestions (creating multiple binaries) and as you (Mark) say it wouldn't hurt...
So why not do both? We could create the extra binaries to bring Python on Windows inline with the unix conventions for command line invocations, and the new launcher can follow on as a nice addition.
Note that the discussions about the Python installer adding to the PATH won't be *ended* by the creation of the installer. A typical install on a Unix-like system adds various other utilities to the path that merely adding the top-level of your Python install on Windows still doesn't add. In particular distutils installed scripts go into a subdirectory of your Python install.
The distutils scripts are a good point. To be honest, apart from the "file association" issue, I can't see much advantage in doing both - if all Python directories end up on your path such that "python3 foo.py" magically works, then the launcher script is adding complexity without bringing much to the table. Further, I'm somewhat skeptical that the file associations are used by that many people in the real world - currently when you double-click on a script you get a temp console created, and should a traceback be raised, you get to see it for about 2ms before the console is destroyed. Some people may be .pyw to avoid that, but then their script has to go to extraordinary lengths to display such errors in a UI of some kind. I suspect most people just find it more convenient to launch such scripts from a console. Maybe a quick poll on python-list would be reasonable...
The launcher program could thrive without *having* to be part of a standard Python install. Offering it separately makes sense even if it *is* included. If we do both then users can vote with their feet. Personally I suspect that many people, particularly new programmers, will appreciate the launcher but more advanced developers will want more precise control (and similarity to unix for command line invocations). I agree with you about file associations. They are useful for .pyw programs (like IDLE), but not for scripts. All the best, Michael
Cheers,
Mark
-- http://www.voidspace.org.uk/ May you do good and not evil May you find forgiveness for yourself and forgive others May you share freely, never taking more than you give. -- the sqlite blessing http://www.sqlite.org/different.html