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

Ron Adam rrr at ronadam.com
Thu Oct 22 07:06:35 CEST 2009

Guido van Rossum wrote:
> I propose a moratorium on language changes. This would be a period of
> several years during which no changes to Python's grammar or language
> semantics will be accepted. The reason is that frequent changes to the
> language cause pain for implementors of alternate implementations
> (Jython, IronPython, PyPy, and others probably already in the wings)
> at little or no benefit to the average user (who won't see the changes
> for years to come and might not be in a position to upgrade to the
> latest version for years after).
> The main goal of the Python development community at this point should
> be to get widespread acceptance of Python 3000. There is tons of work
> to be done before we can be comfortable about Python 3.x, mostly in
> creating solid ports of those 3rd party libraries that must be ported
> to Py3k before other libraries and applications can be ported. (Other
> work related to Py3k acceptance might be tools to help porting, tools
> to help maintaining multiple versions of a codebase, documentation
> about porting to Python 3, and so on. Also, work like that going on in
> the distutils-sig is very relevant.)
> Note, the moratorium would only cover the language itself plus
> built-in functions, not the standard library. Development in the
> standard library is valuable and much less likely to be a stumbling
> block for alternate language implementations. I also want to exclude
> details of the CPython implementation, including the C API from being
> completely frozen -- for example, if someone came up with (otherwise
> acceptable) changes to get rid of the GIL I wouldn't object.
> But the moratorium would clearly apply to proposals for anonymous
> blocks, "yield from" (PEP 380), changes to decorator syntax, and the
> like. (I'm sure it won't stop *discussion* of those proposals, and
> that's not the purpose of the moratorium; but at least it will stop
> worries elsewhere that such proposals might actually be *accepted* any
> time soon.)

++1  Yay!

I really like the idea of keeping the core small, simple, and efficient, 
and having most of the real interfacing and data processing *magic* done 
through libraries.  So yes, please refocus development efforts to improving 
the library.

I think if a library could benifit substantually from some core 
improvement, then that can be discussed at that time. Such improvement to 
the core will be for a real concrete need to enable functionality in an 
extension or library, rather than improving the core with expectations of 
having some unknown abstract or perceived benefit later.

Ron Adam

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