Feature Requests item #925537, was opened at 2004-03-29 19:28 Message generated for change (Comment added) made by gbrandl You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=355470&aid=925537&group_id=5470
Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: None Group: None >Status: Closed >Resolution: Rejected Priority: 4 Private: No Submitted By: Jim Jewett (jimjjewett) Assigned to: Nobody/Anonymous (nobody) Summary: dir(mod) OK or use vars(mod).keys()? Initial Comment: The documentation on dir() notes that its behavior may change across releases. Several library modules use dir(x) in ways that might break if it changed too much. Should these be changed to use vars(obj).keys() (and possibly sort()), or should the note on dir() be removed? My own preference would just be to provide some guidance, such as "The output of dir() will always include all public variables which do not have a magic meaning." I realize that the standard library itself could be updated if dir() changes in an uncomfortable way. My real concern is which spelling to use in my own code. The library examples suggest a simpler (and clearer) dir(), but the documentation still says otherwise. A quick search for modules using dir() showed possible trouble in at least cgitb, cmd, FCNTL, inspect, optparse, os, pickle, rlcompleter, SimpleXMLRPCServer, TERMIOS, tokenize, unittest, and urllib2. ---------------------------------------------------------------------- >Comment By: Georg Brandl (gbrandl) Date: 2007-03-16 08:31 Message: Logged In: YES user_id=849994 Originator: NO Now that we have __dir__(), I think this is "rejected". ---------------------------------------------------------------------- Comment By: Neal Norwitz (nnorwitz) Date: 2007-03-16 06:02 Message: Logged In: YES user_id=33168 Originator: NO Has anything happened? Is this still relevant? ---------------------------------------------------------------------- Comment By: Raymond Hettinger (rhettinger) Date: 2004-05-21 06:05 Message: Logged In: YES user_id=80475 One possible change is in the works. Someone, suggested that dir() starting including the __name__ attribute. ---------------------------------------------------------------------- Comment By: Tim Peters (tim_one) Date: 2004-03-31 00:51 Message: Logged In: YES user_id=31435 Ya, dir() was *intended* to be a convenience for use at the interactive shell. I expect the only promise Guido wants to make about it is that it will show him stuff he finds interesting as Python changes <0.7 wink>. ---------------------------------------------------------------------- Comment By: Martin v. Löwis (loewis) Date: 2004-03-30 21:09 Message: Logged In: YES user_id=21627 Ok, marking it as a feature request then: Explicitly pointing out that behaviour may change in the future has usually been done because change in behaviour is anticipated, or has happened in the past. Giving stronger guarantees about future versions a feature that is currently not provided. ---------------------------------------------------------------------- Comment By: Jim Jewett (jimjjewett) Date: 2004-03-30 15:28 Message: Logged In: YES user_id=764593 The ideal fix would be in documentation (and therefore policy). I want to do something like import_list = [x for x in dir(other_mod) if wanted(x)] It happens to work today on my machine, but the documentation says that dir(x) may return different results in different releases. This means that I can't safely use it in released code. If there were some indication that dir(module) would continue to return the same names as vars(module).keys(), then I could use it. If the differences were only in variables not intended for export, that would also be OK -- but dir does not current promise this. ---------------------------------------------------------------------- Comment By: Martin v. Löwis (loewis) Date: 2004-03-29 22:11 Message: Logged In: YES user_id=21627 I fail to see a bug. Which specific usage of dir() does not work as intended? ---------------------------------------------------------------------- Comment By: Jim Jewett (jimjjewett) Date: 2004-03-29 19:58 Message: Logged In: YES user_id=764593 Correction: "The output of dir (module) will always include ..." The most common use is figuring out what to do with (import from) a module. Symmetry suggests the same for a no-argument call or a class or type object, but object instances do not use their __dict__ for their attributes; the results are already different there. -jJ ---------------------------------------------------------------------- Comment By: Jim Jewett (jimjjewett) Date: 2004-03-29 19:39 Message: Logged In: YES user_id=764593 If there concern is over attributes that are "public" but don't exist until called, then most uses of dir and vars are already broken. An alternative reasonable promise would be The output of dir(obj) will always include all (public?, non-magical?) names in vars(obj).keys(). ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=355470&aid=925537&group_id=5470 _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
