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

Jim Jewett jimjjewett at gmail.com
Fri Oct 23 03:22:16 CEST 2009

On Thu, Oct 22, 2009 at 3:08 PM, Guido van Rossum <guido at python.org> wrote:
> Anyway, the "Python core" includes a lot of stuff that isn't covered
> by the moratorium (which only prohibits changes to syntax and
> associated semantics, not implementation issues).

Changes to semantics are rare enough that I'm not sure a moratorium
(but allowing bug fixes) would matter.  (Particularly if you stick to
the claim that details of import resolution are

I have no opinion on changes to syntax; they're already uncommon, but
saying they'll wait until 2013 doesn't bother me.

The limit on builtins may be more of a problem.  For example, I liked
Brett's work on signatures. If he gets motivated to work on it again,
I don't want him to say "Drat; I really need access to this one extra
function attribute, which isn't currently exposed at the python level.
 I guess I'll have to wait a few years."

It would be reasonable to say that changes to builtins will be rare,
and will typically be strictly additions to functionality, as though
they were replaced by a subclass which overrode nothing except that
certain Exceptions were now handled internally.  (In other words, *if*
the name previously existed, it either keeps the same meaning, or gets
wrapped in something that just calls the old meaning as a try suite,
with all new functionality inside the except suite.)


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