[Python-Dev] The bytes type (original) (raw)

James Y Knight foom at fuhm.net
Tue Jan 16 23:07:08 CET 2007

On Jan 16, 2007, at 2:35 PM, Guido van Rossum wrote:

Mainly I'd just like to see "allowing the ability to write code which is portable between 2.5 and 3.0" as an explicit goal of the python 3.0 release. I trust that if the developers agree upon that as being a goal, the right things would happen, whatever they may be for the specific change in question. Well, there's the crux. That is an explicit NON-goal. It always has been. It would add tons of constraints to Python 3000, and the net effect would be that everybody would continue to code in the 2.5 dialect, making the intended cleanup of the language ineffective.

Okay. I think this is a mistake. Everyone will continue to code in a
2.5-compatible dialect for the immediate future, because their code
needs to continue to function in 2.5. As I keep pointing out, the
language cleanup doesn't have to be all at once: remove all the
already-replaced features now, and deprecate a bunch more things for
removal a few releases later. That'd allow transition to 3.0 to occur
during the time when people have to write in a 2.5-compatible
dialect, anyhow. Otherwise, they'll be writing to 2.5-ONLY that won't
run on 3.0 at all.

We are planning various other ways of providing conversion help. The most promising at this point is to make the following an explicit goal of Python 2.6 and Python 3000: make it possible to write code that runs under 2.6, and that, after automatic conversion using the 2to3 refactoring tool (see sandbox/2to3), runs under 3.0, without requiring manual patching up of the output of the refactoring tool.

Given that my ideal is not going to happen, I guess I'll have to be
content with this. It WILL allow code to be converted incrementally
to be compatible with Python 3.X (which is very important!), but,
unfortunately, not for many years after Py3.0's release. (since the
code can't be made portable until Python 2.6 has been out long enough
for that to become a reasonable minimum requirement).

But, a delayed migration strategy is certainly much much better than
no migration strategy, so it's not all doom and gloom.

But, anyhow, that's enough from me. My opinion has been made known,
and disagreed with by (I think) all the prominent python developers.
So now, I'll let it drop and go get some work done.

Thanks for listening, James

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