[Python-Dev] Spreading the Python 3 religion (was Re: PEP 414 (original) (raw)

Stephen J. Turnbull stephen at xemacs.org
Wed Feb 29 08:23:53 CET 2012

martin at v.loewis.de writes:

One thing that the PEP will certainly achieve is to spread the myth that you cannot port to Python 3 if you also want to support Python 2.5. That's because people will accept the "single source" approach as the one right way, and will accept that this only works well with Python 2.6.

Please, Martin, I dislike this idea as much as you do. (There was no -1 from me, though, because I don't work in the context of the claimed use cases at all, but lots of people obviously find them persuasive.)

But in respect of myth-spreading, the problem with the PEP is the polemic tone. (Yeah, I've seen Armin's claim that it's not polemic. I disagree.) The unqualified claims that "2to3 is insufficient" and the PEP will "enable side-by-side support" of Python 2 and Python 3 by libraries are too extreme, and really unnecessary in light of Guido's logic for acceptance.

As far as I can see, like 2to3, like u()/b(), this PEP introduces a device that will be the most convenient approach for some use cases. If it were presented that way, with recommendation for its use restricted to the particular intended use case, I don't think it would have a huge effect on people's perception of the difficulty of porting in general, including multiversion support including 2.5. If others want to use it, even though you and I think that's a bad idea, well, we can blog, and "consenting adults" covers those users.

On the other hand, implementation of the PEP itself should have a positive effect on the community's perception of python-dev's responsiveness to its pain. Ie, a lot of us feel strongly that this is the wrong thing to do in principle -- but we're gonna do it anyway, because part of the community wants it.

So, let's work on integrating this PEP into the more general framework of recommendations for porting Python 2 code to Python 3 and/or developing libraries targeting both.

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