пятница, 28 декабря 2012 г., 14:37:46 UTC+6 пользователь Aymeric Augustin написал: > > 2012/12/28 Karen Tracey <kmtr...@gmail.com <javascript:>> > >> On Thu, Dec 27, 2012 at 7:15 PM, Aymeric Augustin < >> aymeric....@polytechnique.org <javascript:>> wrote: >> >>> 2) under Python 2.x __str__ is implemented as __unicode__ >>> encoded to utf8. >>> >>> >>> Yes, this is a legacy behavior that I strongly disagree with. It >>> makes __str__ / __unicode__ handling for Model subclasses >>> exceedingly sketchy.* The only reason why I didn't remove >>> it is backwards compatibility. >>> >> >> I'm curious what would you do instead, if backward-incompatibility were >> not a concern? > > > In Python __unicode__ is __str__ + decode(sys.getdefaultencoding()): > http://docs.python.org/2/reference/datamodel.html#object.__unicode__ > > Django reverses this behavior for Model subclasses and uses utf-8. > > I was first exposed to unicode handling in Python via Django and > it took me a long time to discover that writing a __unicode__ method > wasn't the canonical way to define an object's string representation. > > If we set aside backwards-compatibility, I would probably > define a conventional, Django-specific method (eg. __display__) > and derive __unicode__ and __str__ from there, according to > Django's rules. Not using Python's default names makes it explicit > that Django adds specific behavior. This vastly simplifies the > definition of __str__ and __unicode__ in Python 2 and 3, and also > avoids the semantic issue of __str__ returning unicode on Python 2 > under @python_2_unicode_compatible. > > An alternative would be to provide an explicit way to change > Python's behavior -- either a decorator or a class attribute. > Though this isn't going to be very DRY. > > I haven't had issues with using utf-8 instead of the system charset, > but Mikhail seems to suggest it can be a problem on Windows. > Using the system charset, like Python does, might be less surprising. > I don't have enough experience to tell. This won't be a problem for > displaying objects in templates, because they're rendered in unicode. > > There is no a single "system charset" and that's the problem :)
>>> import sys>>> import locale>>> sys.getdefaultencoding()'ascii'>>> >>> locale.getpreferredencoding()'cp1251'>>> sys.stdout.encoding'cp866' (REPL in Windows XP with Russian locale with all defaults; sys.stdout.encoding would be None for scripts). It is not possible (as far as I can tell) to encode __str__ or __repr__ results to some encoding (except 7bit ascii) and expect it to work reliably. > -- > Aymeric. > > -- You received this message because you are subscribed to the Google Groups "Django developers" group. To view this discussion on the web visit https://groups.google.com/d/msg/django-developers/-/Tl53rAjzILQJ. To post to this group, send email to django-developers@googlegroups.com. To unsubscribe from this group, send email to django-developers+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-developers?hl=en.
