[Python-Dev] Re: PEP 279 (original) (raw)

Guido van Rossum guido@python.org
Fri, 29 Mar 2002 01:41:05 -0500

> 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/)