But why? [LWN.net]

But why?

Posted Jul 18, 2018 9:37 UTC (Wed) by tialaramex (subscriber, #21167)
Parent article: Python post-Guido

It remains unclear to me why language developers are so sure that they _need_ a mechanism by which controversial changes to a successful languages get made. I very much doubt that it matters which hopelessly inappropriate mechanism you choose, the problem of "Let's make this change lots of people oppose" isn't fixed by having a triumvirate, or choosing by coin tosses, or apantomany ("if the next bird I see is a swan, we're applying the patch").

But why?

Posted Jul 18, 2018 15:02 UTC (Wed) by malefic (subscriber, #37306) [Link] (3 responses)

> the problem of "Let's make this change lots of people oppose" isn't fixed by having a triumvirate

PEP 572 is an outlier. Most PEPs are accepted or rejected without so much fuss, even when there's some opposition. PEP 498 (Literal String Interpolation) in Python 3.6 was also vigorously opposed ("why do we ever need a *fourth* formatting method??!"), but is now accepted as one of the best features of Python 3. The BDFL is there to make the final decision, however unpopular at the time of inclusion, and to provide overall design consistency through their vision and taste. This is much better than making decisions through a coin toss.

But why?

Posted Jul 19, 2018 14:42 UTC (Thu) by tialaramex (subscriber, #21167) [Link] (2 responses)

[Meant to post this some time ago but forgot LWN has a "confirm" step instead of editing comments]

But do you think ramming through PEP 498 worked out better because this is generally a good way to do things and PEP 572 was just bad luck?

I'm looking back at things like PEP 414 (unicode literals in Python 3 so that more Python 2 code "just works") and I see plenty of effort put into figuring out what's actually objectionable here, let's narrow this down and do just the minimum possible to make the most people happy while annoying as few as possible.

My feeling is that with PEP 498 there was an attempt to shortcut, "I can't be bothered to persuade these people that I'm right, so we'll just do it, and then hopefully they'll come along".

But that's doubly risky, the least awful outcome is that you were right but you alienate loads of people and cause unnecessary strife, which seems to be what Guido thinks happened here. And actually it's also possible that since you insisted on doing it anyway you were wrong, you will eventually _realise_ you were wrong and so either it's going to get reversed out or the language will fade away ("Remember when Python didn't have that stupid assignment bug?").

Again, I bring this up because we're talking about programming languages here. This is not a penalty shoot-out, we have great luxury of time. What would be the negative consequences of PEP 572 taking twelve months, or five years to search for consensus ? Other than those in favour didn't want to wait?

But why?

Posted Jul 20, 2018 9:30 UTC (Fri) by NAR (subscriber, #1313) [Link]

"What would be the negative consequences of PEP 572 taking twelve months, or five years to search for consensus ? Other than those in favour didn't want to wait?"

It raises the possibility of "filibuster" and the language getting stuck/obsolete.

But why?

Posted Jul 20, 2018 11:55 UTC (Fri) by edgewood (subscriber, #1123) [Link]

My sense of why not take twelve months (from the reporting and light skimming of some of the threads on the mailing list) is that they might have been happy to have a twelve month discussion that made progress the whole time. The actual discussion had a lot of addressing the same points over and over and over again. I can understand why they didn't want to continue doing that.