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

MRAB python at mrabarnett.plus.com
Wed Oct 21 21:29:58 CEST 2009

Guido van Rossum wrote:
> On Wed, Oct 21, 2009 at 11:26 AM, Raymond Hettinger <python at rcn.com> wrote:
>> [Guido van Rossum]
>>> Note, the moratorium would only cover the language itself plus
>>> built-in functions, not the standard library.
>> That makes sense.
>> There may be a few areas that still have some rough edges where you
>> may want to allow changes if needed (tweaks to the nested with-statement
>> syntax, bytes/text interaction, star-args unpacking, or string formatting).
>> These areas probably have not been exercised much and there may still be
>> problems that need to be ironed-out.  I don't have anything specific
>> in mind.  Am just thinking that those features aren't yet mature.
> No, the moratorium would freeze the language at the 3.1 version, at
> least for 3.2 and 2.7 and possibly 3.3 (see my earlier post). Allowing
> for exceptions like these provides too much wiggle room. (E.g is the
> decorator syntax broken?)
> Outright bugs in the implementation should be excepted (subject to
> discussion) but the accepted grammar and semantics should be frozen
> unless they are unimplementable.
I'd like there to be the possibility of a change if we were to discover
a case (a corner case, perhaps) where everyone agrees that what Python
is actually doing is unPythonic due to some unforeseen combination of
factors (and I'm not talking about mutable default parameters). Who
knows, it could happen! :-)

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