[Python-Dev] Re: PEP 279

[Guido van Rossum]

> > 1. indexed()

> >    I don't like the name "indexed"; adjectives do not make good
> >    function names.  Maybe iterindexed()?
> 
> Any reasonable name is fine with me.
> Originally, I proposed index() but was talked out of it.
> 
> I like itercount() or enumerate().  The reason is that this
> function can work with any iterable including those that
> do not have numeric indices (such as dictionaries).
> Counting or enumeration is what is really happening.

I don't like either of those, you don't seem to like iterindexed(), so
we'll have to think more about a name.

> for linenum, line in itercount( alinelist, 1 ):
>     print 'Line %03d:  %s' % (linenum, line)

You can do that like this:

  for linenum, line in itercount(alinelist):
      print 'Line %03d:  %s' % (linenum+1, line)

> In summary, here is my order of preference:
> 1.  itercount(collection, countfrom=0, stop=None)   # best
> 2.  itercount(collection, countfrom=0)                      # almost
> excellent
> 3.  itercount(collection)                                            # good
> enough

I really hate the alternate count option, so let's agree to pick 3
(with a different name).

> > 2. Generator comprehensions

> If implementation effort were taken out of the equation, would the
> balance shift back to a +1 ?    In other words, if I find a developer
> who wants this badly enough to work with me to get it implemented,
> do we have a go?

Not really.  After it's written (and debugged!), it's still a lot of
code that needs to be maintained (we're already thinking about
rewriting the bytecode generators, there's Jython, and so on) for a
very slight benefit.  What other feature would you give up in order to
have this on?

If the only way to get you to stop asking for this is a -1 from me,
I'll give it a -1.

> Several commenters wanted this one quite a bit.  An excerpt: "This
> rules.  You rock."

Yeah, if I left Python's design to Ping, it would become quite the
clever hack. :-)

> > 3. Generator exception passing

> I need help from others on py-dev who can articulate the need clearly.
> For me, it's as plain as day and I don't know what to say to convey the
> message better than it is expressed in the PEP.

Too bad.  This one gets a big fat -1 until there's a good motivational
section.

--Guido van Rossum (home page: http://www.python.org/~guido/)