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[Python-Dev] Re: [Idle-dev] Forward progress with full backward compatibility
Peter Funkdscherer@cmu.edu (David Scherer), python-dev@python.org
Mon, 10 Apr 2000 18:54:09 +0200 (MEST)
Hi!David Scherer onidle-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 installerprogram, 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 orglobal python_1_6 #implies global old_division or global python_1_7 #may be implies global new_divisionmay be we can solve another issue just discussed on python_dev withglobal source_iso8859_1 orglobal source_utf_8Cute 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 archivesare open to anyone and writing to the list is also open to anybody.Only subscription is closed. I don't know why.Regards, PeterP.S.: Redirected Reply-To: to David andpython-dev@python.org !-- Peter Funk, Oldenburger Str.86, D-27777 Ganderkesee, Germany, Fax:+49 4222950260office: +49 421 20419-0 (ArtCom GmbH, Grazer Str.8, D-28359 Bremen)
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