On 7 June 2018 at 17:55, Ethan Merritt <merr...@u.washington.edu> wrote:
> My basic concern is that python language development has broken existing > code in the past. Frequently. They feel free to change things at any > point, > even fundamental things like the meaning of the arithmetic operation > "divide". > You may be perfectly happy with the current state of the python 3 language, > but based on past history that state will change and change again and > sooner > or later your current code will stop working. My concern is not the > state of the language at any given point in time, but the fact that it > has been unstable for the past two decades and the worry that this > instability > will continue into the future. > The division example was in my opinion handled rather well, as the default behaviour was consistent in Python 2 and is consistent within Python 3, but different between the two. If you wanted the new (3) behaviour in the old (2) Python you would declare *from __future__ import division *at the top of your file, and you can migrate one file at a time. The default Python 2.7 behaviour is the same as it was in Python 1.0. I gather that one cluster of recent breakage is incompatible changes to > text handling. I cannot speak to this issue from personal experience, > but here is a pointer to recent complaints/arguments/counter-arguments. > https://lwn.net/Articles/741176/ Unicode is difficult in any language. (pun possibly intended) It is a big thing for any 2->3 migration as you have to consciously decide what is text and what is data and how you handle the boundaries. I kind of agree with all of those points. > The sticky point is if you are likely to be one of the people on the > receiving end of that nagging. > I am on both sides of this argument. I try to drive Python 3 compatibility for DIALS, which involves nagging people responsible for upstream packages that we rely on. However, you will help me by nagging me, because then I can point other developers to users who want this. Otherwise the whole migration thing can look like an academic exercise. So please do nag. (I don't want to end up at *another* cliff edge in 2020, having just gone over the one in 2019.) -Markus ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
