[Python-ideas] Proposal: Moratorium on Python language changes

Dino Viehland dinov at microsoft.com
Wed Oct 21 21:07:11 CEST 2009

Guido wrote:
> > I think a fair amount of our time and work is better spent on the
> > stdlib, various implementation(s) and things of that nature
> > (ecosystem).
> Of course, no moratorium can stop people from *proposing* changes, but
> it helps core developers and others who "just want to get stuff done"
> focus if they know we're not changing the language for quite a while.
> Effectively the moratorium would freeze the language at the 3.1
> version at least for 3.2 and possibly for 3.3. Also 2.7 could not add
> language changes except possibly changes to keep up with 3.1 (but only
> if *very* strict backwards compatibility with 2.6 is maintained also
> -- I want the upgrade from 2.6 to 2.7 to be a breeze for everyone).
> Obviously there are many things we could change in the standard
> library that would still affect the ability to upgrade easily (see the
> recent issues with 2.6.3 and 2.6.4), and we should be exercising a lot
> of restraint in this are as well. But language changes affect other
> implementations the most (I think). They also coincidentally speak
> most to the imagination of the young, eager-to-add-their-pet-feature
> amateur language designer crowd who so often fill python-ideas with
> heated discussions.

This generally sounds nice for us and will make it easier to catch up
to 3.x as well as make it easier to continue to flush out other missing
built-in modules.  But I would actually be really happy with just a partial 
freeze though - I actually find support for new standard library features
is typically the biggest hit for us and that core language features (modulo
import related features which are always difficult ) have generally not 
been an issue.

For example consider multiprocessing - which IronPython still doesn't 
support.   That's a much bigger work item than everything that changed 
related to parsing in 2.6.  New built-in functions can also be a huge 
pain - again compare float.fromhex to everything that happened to the 
parser in 2.6.  I'm pretty sure I spent more time on float.fromhex even 
w/ the already existing awesome test suite.

So I definitely think not adding significant new functionality to the core
interpreter would be great but from an alternate implementation perspective
I'd also be happy to see some wiggle room on small new features.  

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