Leo Breebaart <l...@lspace.org> writes: > Arnaud Delobelle <arno...@googlemail.com> writes: > >> Descriptors to the rescue :) >> >> def read_body_from(filename): >> print "** loading content **" >> return "<content of '%s'>" % filename >> >> # This is a kind of class property >> class TemplateFilename(object): >> def __get__(self, obj, cls): >> return "%s.tmpl" % cls.__name__ >> >> # And this is a kind of cached class property >> class TemplateBody(object): >> def __get__(self, obj, cls): >> try: >> return cls._body >> except AttributeError: >> cls._body = read_body_from(cls.template_filename) >> return cls._body >> >> class Foo(object): >> template_filename = TemplateFilename() >> template_body = TemplateBody() >> >> class FooA(Foo): >> pass >> >> class FooB(Foo): >> pass > > Very enlightening, thanks! > > By the way, I completely agree with the other posters in this > thread that intricate solutions such as this are likely to be > overkill, especially since at this point I have no idea if the > inefficiency of reading those templates multiple times would at > all matter (frankly, I'd doubt it). But it's certainly been > educational to learn about these techniques.
Writing programs is a great way to keep learning :) > One observation: if I implement the descriptor solution as given > above, the code works perfectly, but running the code through > pychecker now causes an error, because that again causes an > attempt to read from the non-existant base class template file > "Foo.tmpl"... As someone said before, you could just provide a dummy Foo.tmpl file. -- Arnaud -- http://mail.python.org/mailman/listinfo/python-list
