[Python-Dev] Thoughts fresh after EuroPython

Terry Reedy tjreedy at udel.edu
Sat Jul 24 23:05:58 CEST 2010

On 7/24/2010 10:08 AM, Guido van Rossum wrote:

> - Commit privileges: Maybe we've been too careful with only giving
> commit privileges to to experienced and trusted new developers. I
> spoke to Ezio Melotti and from his experience with getting commit
> privileges, it seems to be a case of "the lion is much more afraid of
> you than you are afraid of the lion". I.e. having got privileges he
> was very concerned about doing something wrong, worried about the
> complexity of SVN, and so on. Since we've got lots of people watching
> the commit stream, I think that there really shouldn't need to be a
> worry at all about a new committer doing something malicious, and
> there shouldn't be much worry about honest beginners' mistakes either
> -- the main worry remains that new committers don't use their
> privileges enough.

My initial inclination is to start with 1 or 2 line patches that I am 
99.99% certain are correct. But it has occurred to me that it might be 
better for Python if I were willing to take a greater than 1/10000 
chance of making a mistake. But how much greater? What error rate do 
*you* consider acceptable?

> - Concurrency and parallelism: Russel Winder and Sarah Mount pushed
> the idea of CSP
> (http://en.wikipedia.org/wiki/Communicating_sequential_processes) in
> several talks at the conference. They (at least Russell) emphasized
> the difference between concurrency (interleaved event streams)

This speeds perceived and maybe actual responsiveness to user input.

> and parallelism (using many processors to speed things up).

This reduces total time.

> Their
> prediction is that as machines with many processing cores become more
> prevalent, the relevant architecture will change from cores sharing a
> single coherent memory (the model on which threads are based) to one
> where each core has a limited amount of private memory, and
> communication is done via message passing between the cores.

I believe this is a prediction that current prototypes, if not current 
products, will be both technically and commercially successful. My 
impression is enough better than 50/50 to be worth taking into account. 
It does not seem like much of a leap from private caches that write 
through to common memory to private memory that is not written through, 
especially on 64 bit machines with memory space to spare.

> - After seeing Raymond's talk about monocle (search for it on PyPI) I
> am getting excited again about PEP 380 (yield from, return values from
> generators). Having read the PEP on the plane back home I didn't see
> anything wrong with it, so it could just be accepted in its current
> form. Implementation will still have to wait for Python 3.3 because of
> the moratorium. (Although I wouldn't mind making an exception to get
> it into 3.2.)

While initially -0, I now think the moratorium was a good idea. It seems 
to be successful at letting and even encouraging people to target 3.2 by 
working with 3.1. A big exception like this would probably annoy lots of 
people who had *their* 'equally good' ideas put off and might annoy 
alternative implementors counting on core 3.2 being as it. So the only 
exception I would make would one that had a really good technical 
reason, like making Python work better on multi-core processors

> - This made me think of how the PEP process should evolve so as to not
> require my personal approval for every PEP. I think the model for
> future PEPs should be the one we used for PEP 3148 (futures, which was
> just approved by Jesse):


Terry Jan Reedy

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