[pypy-dev] Fwd: Discussion with Guido van Rossum and (hopefully) core python-dev on scientific Python and Python3

[Serhat Sevki Dincer]

I will take the liberty to forward this topic on "scientific python"
to pypy list, since numpy work on pypy has progressed a lot,
apparently, and it does concern pypy too, i guess..

Date: Mon, 13 Feb 2012 13:55:45 -0800
From: Fernando Perez <fperez.net at gmail.com>
Subject: [Matplotlib-users] Discussion with Guido van Rossum and
       (hopefully) core python-dev on scientific Python and Python3
To: Discussion of Numerical Python <numpy-discussion at scipy.org>
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Hi folks,

[ I'm broadcasting this widely for maximum reach, but I'd appreciate
it if replies can be kept to the *numpy* list, which is sort of the
'base' list for scientific/numerical work.  It will make it much
easier to organize a coherent set of notes later on.  Apology if
you're subscribed to all and get it 10 times. ]

As part of the PyData workshop (http://pydataworkshop.eventbrite.com)
to be held March 2 and 3 at the Mountain View Google offices, we have
scheduled a session for an open discussion with Guido van Rossum and
hopefully as many core python-dev members who can make it.  We wanted
to seize the combined opportunity of the PyData workshop bringing a
number of 'scipy people' to Google with the timeline for Python 3.3,
the first release after the Python language moratorium, being within
sight: http://www.python.org/dev/peps/pep-0398.

While a number of scientific Python packages are already available for
Python 3 (either in released form or in their master git branches),
it's fair to say that there hasn't been a major transition of the
scientific community to Python3.  Since there is no more development
being done on the Python2 series, eventually we will all want to find
ways to make this transition, and we think that this is an excellent
time to engage the core python development team and consider ideas
that would make Python3 generally a more appealing language for
scientific work.  Guido has made it clear that he doesn't speak for
the day-to-day development of Python anymore, so we all should be
aware that any ideas that come out of this panel will still need to be
discussed with python-dev itself via standard mechanisms before
anything is implemented.  Nonetheless, the opportunity for a solid
face-to-face dialog for brainstorming was too good to pass up.

The purpose of this email is then to solicit, from all of our
community, ideas for this discussion.  In a week or so we'll need to
summarize the main points brought up here and make a more concrete
agenda out of it; I will also post a summary of the meeting afterwards
here.

Anything is a valid topic, some points just to get the conversation started:

- Extra operators/PEP 225.  Here's a summary from the last time we
went over this, years ago at Scipy 2008:
http://mail.scipy.org/pipermail/numpy-discussion/2008-October/038234.html,
and the current status of the document we wrote about it is here:
file:///home/fperez/www/site/_build/html/py4science/numpy-pep225/numpy-pep225.html.

- Improved syntax/support for rationals or decimal literals?  While
Python now has both decimals
(http://docs.python.org/library/decimal.html) and rationals
(http://docs.python.org/library/fractions.html), they're quite clunky
to use because they require full constructor calls.  Guido has
mentioned in previous discussions toying with ideas about support for
different kinds of numeric literals...

- Using the numpy docstring standard python-wide, and thus having
python improve the pathetic state of the stdlib's docstrings?  This is
an area where our community is light years ahead of the standard
library, but we'd all benefit from Python itself improving on this
front.  I'm toying with the idea of giving a lighting talk at PyConn
about this, comparing the great, robust culture and tools of good
docstrings across the Scipy ecosystem with the sad, sad state of
docstrings in the stdlib.  It might spur some movement on that front
from the stdlib authors, esp. if the core python-dev team realizes the
value and benefit it can bring (at relatively low cost, given how most
of the information does exist, it's just in the wrong places).  But
more importantly for us, if there was truly a universal standard for
high-quality docstrings across Python projects, building good
documentation/help machinery would be a lot easier, as we'd know what
to expect and search for (such as rendering them nicely in the ipython
notebook, providing high-quality cross-project help search, etc).

- Literal syntax for arrays?  Sage has been floating a discussion
about a literal matrix syntax
(https://groups.google.com/forum/#!topic/sage-devel/mzwepqZBHnA).  For
something like this to go into python in any meaningful way there
would have to be core multidimensional arrays in the language, but
perhaps it's time to think about a piece of the numpy array itself
into Python?  This is one of the more 'out there' ideas, but after
all, that's the point of a discussion like this, especially
considering we'll have both Travis and Guido in one room.

- Other syntactic sugar? Sage has "a..b" <=> range(a, b+1), which I
actually think is  both nice and useful... There's also the question
of allowing "a:b:c" notation outside of [], which has come up a few
times in conversation over the last few years. Others?

- The packaging quagmire?  This continues to be a problem, though
python3 does have new improvements to distutils.  I'm not really up to
speed on the situation, to be frank.  If we want to bring this up,
someone will have to provide a solid reference or volunteer to do it
in person.

- etc...

I'm putting the above just to *start* the discussion, but the real
point is for the rest of the community to contribute ideas, so don't
be shy.

Final note: while I am here commiting to organizing and presenting
this at the discussion with Guido (as well as contacting python-dev),
I would greatly appreciate help with the task of summarizing this
prior to the meeting as I'm pretty badly swamped in the run-in to
pydata/pycon.  So if anyone is willing to help draft the summary as
the date draws closer (we can put it up on a github wiki, gist,
whatever), I will be very grateful.  I'm sure it will be better than
what I'll otherwise do the last night at 2am :)

Cheers,

f

ps - to the obvious question about webcasting the discussion live for
remote participation: yes, we looked into it already; no,
unfortunately it appears it won't be possible.  We'll try to at least
have the audio recorded (and possibly video) for posting later on.

pps- if you are close to Mountain View and are interested in attending
this panel in person, drop me a line at fernando.perez at berkeley.edu.
We have a few spots available *for this discussion only* on top of the
pydata regular attendance (which is long closed, I'm afraid).  But
we'll need to provide Google with a list of those attendees in
advance.  Please indicate if you are a core python committer in your
email, as we'll give priority for this overflow pool to core python
developers (but will otherwise accommodate as many people as Google
lets us).