Status of PEPs?

[Thomas Reichelt]

John Roth wrote:

> "Thomas Reichelt" <XXNOSPAMXX at gibts.net> wrote in message
> news:2kfjf7F1nk33U1 at uni-berlin.de...
>> Hello Python-Fans,
>>
>> A few months in the past, I learned the Python language and was very
> pleased
>> of it. I have now written many scripts for myself and this opinion
>> stayed, not to say, it became more intensive.
>>
>> Recently I have discovered the PEP Archive, and my question is now this:
>> There are many open ("under consideration") PEPs that would incorporate
>> useful features into the language, such as the do-while statement, the
>> switch statement or the __main__ function. However, most of these
> proposals
>> are several years old. Though implementations seem to exist for the
>> proposals, no action is taken about them. Why is this so? What has to be
>> done for a proposal to make it into the language?
>>
>> Thank you for answering a dumb question...
> 
> It's not a particularly dumb question. The missing piece is that there
> are a limited number of core developers, and you need to get a
> concensus among them on the Python Dev mailing list that this
> particular proposal is more worthy of their time than other
> competing proposals. You also need to get it past Guido. Also
> note that in two cases you would be adding keywords, which
> impose a significant forwards compatibility issue, while the
> third has a major issue of non-obviousness.
> 
> The proposals you mention all fall into the category of "useful,
> but there are other ways of doing that job that work, are well
> accepted, and are not a significant burden in terms of either
> developer time or comprehensibility."
> 
> Put another way, there was a significant against component in the
> discussion from the "keep Python simple" crowd.
> 
> In other words, to move any of them forward would require submission
> of a complete implementation that would work in the current
> development tree, together with the necessary documentation
> changes, thorough tests, and so on and so forth. That is, someone
> who wants to see any of these in Python needs to do the work
> themselves.
> 
> A good example of this is the work being done by Facundo Batista
> on PEP 327 (Decimal Arithmetic). There's been widespread
> agreement for a long time that something should be done about
> decimal arithmetic, but until he stepped forward, it sat on dead
> center. Now it looks like we're going to get it for Python 2.4,
> so it may be possible for us to get a usable currency type in
> Python 2.5 (building on the decimal type.)

Thank you for your explanation. What I don't understand, though, is that the
PEPs for which an implementation exists aren't discussed further, but are
just lying around in a corner, though there is a significant advantage in
the PEP's proposal. I understand that the introduction of a new keyword is
a drastic change, but Python has good capabilities to compensate for that
(from __future__ ...).

It is clear that most of the proposed syntactic enhancements can be rebuilt
with the existing language, but sometimes only with code duplication or
clumsy constructs.

-- 
greetz tom