[Python-Dev] PEP 3003 - Python Language Moratorium

Steven D'Aprano steve at pearwood.info
Mon Nov 9 00:06:25 CET 2009

On Sun, 8 Nov 2009 11:14:59 am Steven D'Aprano wrote:
> At the very least, I believe, any moratorium should have a clear end
> date. A clear end date will be a powerful counter to the impression
> that Python the language is moribund. It says, this is an exceptional
> pause, not a permanent halt.


No new language features in odd-numbered point releases (3.3, 3.5, ...). 
Even-numbered point releases (3.4, 3.6, ...) may include new language 
features provided they meet the usual standards for new features.

3.2 is a special case: as an even-numbered release, it would normally 
allow new features, but in recognition of the special nature of the 2.x 
to 3.1/3.2 migration, no new language features will be allowed.


* It slows down changes to the language while still allowing 
sufficiently high-standard new features.

* Alternate implementations have a stable language version to aim for. 
Assuming point releases come ever 12-18 months, that stable language 
version will last 2-3 years.

* It doesn't have the psychological baggage of an unconditional ban on 
new features for the indefinite future. It gives a fixed, known 
schedule for when new features will be permitted, without the 
uncertainty of "at the BDFL's pleasure".

Steven D'Aprano

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