On Thu, Sep 4, 2008 at 12:36 PM, Guido van Rossum <[EMAIL PROTECTED]> wrote: > On Wed, Sep 3, 2008 at 9:25 PM, Raymond Hettinger <[EMAIL PROTECTED]> wrote: >> [Brett] >>> I gave a talk last night at the Vancouver Python users group on >>> 2.6/3.0, and I tried the following code and it failed during a live demo: >>> >>> >>> try: pass >>> ... except Exception, Exception: pass >>> File "<stdin>", line 2 >>> except Exception, Exception: pass >>> ^ >>> SyntaxError: invalid syntax >>> >>> Now from what I can tell from PEP 3110, that should be legal in 3.0. >>> Am I reading the PEP correctly? >> >> Don't think so. >> The parens are necessary for a tuple of exceptions >> lest it be confused with the old "except E, v" syntax >> which meant "except E as e". >> >> Maybe in 3.1, the paren requirement can be dropped. > > I would wait longer -- until well after the 2.x line is dead and > buried. It will take some time for every Python user to train their > Python fingers not to type "except E, v:" and we don't want people who > are late in migrating inserting bugs like this in their first 3.x program.
it's probably a good idea to leave the paren requirement in there, but i just reread the PEP myself, and it appears as though no parens is actually supported, specifically: "except AttributeError, os.error:" here: http://www.python.org/dev/peps/pep-3110/#grammar-changes also, and granted this is older info, Guido's 2006 talks seem to hint this as well: - change except clause syntax to except E1, E2, E3 as err: - this avoids the bug in except E1, E2: # meant except (E1, E2) from both of these: ACCU - Apr 2006 (slide 11) http://www.python.org/doc/essays/ppt/accu2006/Py3kACCU.ppt Vancouver Python Workshop - Aug 2006 (slide 13) http://www.vanpyz.org/conference/2006/proceedings/MarygX/Py3KVanPyz.ppt while we can't change the past, we can/should at least update the PEP as well as the current 2.6 and 3.0 docs to specifically state that the parens are required (for now) *and* give an example usage. cheers, -- wesley - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - "Python Web Development with Django", Addison Wesley, (c) 2008 http://withdjango.com wesley.j.chun :: wescpy-at-gmail.com python training and technical consulting cyberweb.consulting : silicon valley, ca http://cyberwebconsulting.com _______________________________________________ Python-3000 mailing list Python-3000@python.org http://mail.python.org/mailman/listinfo/python-3000 Unsubscribe: http://mail.python.org/mailman/options/python-3000/archive%40mail-archive.com
