On Wed, 19 May 2010 00:16:56 -0700, TomF wrote: > Let's say you have a bunch of globals, one of which is a verbose flag. > If I understand the difference, using a module gbls.py: > > # in gbls.py > verbose = False > # elsewhere: > import gbls > gbls.verbose = True > > Using a class: > > # In the main module: > class gbls(object): > def __init__(self, verbose=False): > self.verbose = verbose > > my_globals = gbls.gbls(verbose=True) > ... > some_function(my_globals, ...) > > > If this is what you have in mind, I'm not really seeing how one is good > practice and the other is bad. The OOP method is more verbose (no pun > intended) and I don't see how I'm any less likely to shoot myself in the > foot with it.
Exactly! Both are considered harmful. Best is to avoid the use of globals if possible, not to disguise them by wrapping them in a class. The second case (using a class) is slightly less harmful, because you can set up multiple global namespaces and do this: some_function(my_globals, ...) some_function(other_globals, ...) which at least allows you to replace the globals on demand, but it is still somewhat of a code-smell. Best is to find a way of doing without them. (Note that global constants and functions are usually fine.) Unfortunately, it's rarely possible to do entirely without global settings, except in trivial applications. But what you can do is use Python's dynamic programming to reduce the need to keep globals hanging around: # Untested. def verbose_print(arg, level, verbosity=1): if level <= verbosity: print arg def my_function(arg): my_print(arg, level=2) return arg.upper() if __name__ == '__main__': if '--verbose' in sys.argv: my_print = functools.partial(verbose_print, verbosity=2) elif '--quiet' in sys.argv: my_print = functools.partial(verbose_print, verbosity=0) my_function("hello world") Note that although there is no verbosity global setting, every function that calls my_print will do the right thing (unless I've got the test backwards...), and if a function needs to override the implicit verbosity setting, it can just call verbose_print directly. -- Steven -- http://mail.python.org/mailman/listinfo/python-list