Hi! David Scherer on idle-dev@python.org: [...]

in the interpreter* is fast. In principle, one could put THREE operators in the language: one with the new "float division" semantics, one that divided only integers, and a "backward compatibility" operator with EXACTLY the old semantics: [...] An outline of what I did: [...]

Yes, this really clever. I like the ideas. [me]:

...

2. What should the new Interpreter do, if he sees a source file without a pragma defining the language level? There are two possibilities: [...] 2. Assume, it is a new source file and apply language level 2 to it. This has the disadvantage, that it will break any existing code.

I think the answer is 2. A high-quality script for adding the pragma to existing files, with CLI and GUI interfaces, should be packaged with Python. Running it on your existing modules would be part of the installation process.

Okay. But what is with the Python packages available on the Internet? May be the upcoming dist-utils should handle this? Or should the Python core distribution contain a clever installer program, which handles this?

Long-lived modules should always have a language level, since it makes them more robust against changes and also serves as documentation. A version statement could be encouraged at the top of any nontrivial script, e.g:

python 1.6 [...]

global python_1_5 #implies global old_division or global python_1_6 #implies global old_division or global python_1_7 #may be implies global new_division may be we can solve another issue just discussed on python_dev with global source_iso8859_1 or global source_utf_8 Cute idea... but we should keep the list of such pragmas short.

Personally, I think that it makes more sense to talk about ways to gracefully migrate individual changes into the language than to put off every backward-incompatible change to a giant future "flag day" that will break all existing scripts. Versioning of some sort should be encouraged starting *now*, and incorporated into 1.6 before it goes final.

Yes.

Indeed, but Guido has spoken:

...

Great ideas there, Bruce! I hope you will post these to an appropriate mailing list (perhaps idle-dev, as there's no official SIG to discuss the Python 3000 transition yet, and python-dev is closed).

May be someone can invite you into 'python-dev'? However the archives are open to anyone and writing to the list is also open to anybody. Only subscription is closed. I don't know why. Regards, Peter P.S.: Redirected Reply-To: to David and python-dev@python.org ! -- Peter Funk, Oldenburger Str.86, D-27777 Ganderkesee, Germany, Fax:+49 4222950260 office: +49 421 20419-0 (ArtCom GmbH, Grazer Str.8, D-28359 Bremen)