Hi, I've been thinking more, and I'm really disturbed by this piecemeal approach to getting Python 3, as least as far as it impacts *users* (for developers it is great).
As mentioned before, I've been writing tons of code using Python 3 for the last two weeks. There are *many* subtle ways in which this python2 --> python3 switch will flat out break people's code/brains, which go far beyond just the print statement. Frankly, I think trying to gently migrate *end users/college teachers* in multiple steps is just going to make matter worse. For example, I'm finally using print as a function. Cool. Now (this just happened a minute ago), I write: [blah... for a,b in x.iteritems()] where x is a dictionary. This is/was the optimal way to iterate over the key/values of a dictionary in Python2. In Python3, iteritems is just completely gone. There's surely tons of other things like this. We need a real strategy for migrating users to Python3, and definitely not some half-way thing that deals only with the print statement. ** If we break compatibility in the *slightest* for Python3, I think it should only happen *once*. ** The last thing we want is: - I upgraded to Sage-7.3 and *all* my 100s of worksheets I use in teaching broke due to print statements. I spent 10 hours going through and fixing them all -- ugh. Misery. Then... - I upgraded to sage-7.5 and all my code broke again due to (some other python3 feature we enable)... I spent 10 hours going through and fixing them all -- ugh. Misery and pain. Then... - I upgraded to Sage-8.0 and all my code broke badly again due to Sage switching to Python3! I spent hours rewriting my code a third time, running scripts (like the 2-to-3 convertor, but preparser aware?), etc. If we are going to force users to rewrite everything to work, then let's do it all at once, rather than multiple times. And automate it as much as possible. Because of SageMathCloud, I know for a fact that lots of teachers write lots of code using Jupyter notebooks and Sage worksheets, which of course has print statements all over and other python2-isms. They don't have the time to deal with stuff like this. If anything involving maintaining their work takes "10 hours", they will like just not do it ever. If they use SMC, I'll probably just make it so they can stay with sage-7.2 "forever", just like people stick with gap3 and python2 forever. However, if we make switching from Python2 to Python3 trivial/smooth/easy for end users, they'll all switch no problem and love it. -- William On Tue, May 24, 2016 at 12:24 PM, Frédéric Chapoton <fchapot...@gmail.com> wrote: > I agree with Johann's proposal, with X=1 year as William proposed. > > The doc will very soon already have print() everywhere. > > I have contacted at least one author of the French book. They want to make a > revised edition and an English traduction, and they will use print(). > > Who is volunteering to write the parser ? > > Frederic > > > Le mardi 24 mai 2016 20:52:09 UTC+2, Jori Mäntysalo a écrit : >> >> On Tue, 24 May 2016, Johan S. R. Nielsen wrote: >> >> > 1) For year, issue only a deprecation *the first time* "print a" is used >> > in a session. >> > 2) After that, for X years, issue a deprecation warning *every time* >> > "print a" is used. >> > 3) After that, remove support for "print a" completely. >> >> 0) For a year(?), distribute version of Sage where every example uses only >> print(). Contact writers of Sage textbook etc. >> >> -- >> Jori Mäntysalo > > -- > You received this message because you are subscribed to the Google Groups > "sage-devel" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sage-devel+unsubscr...@googlegroups.com. > To post to this group, send email to sage-devel@googlegroups.com. > Visit this group at https://groups.google.com/group/sage-devel. > For more options, visit https://groups.google.com/d/optout. -- William (http://wstein.org) -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
