Steven Bethard wrote: > Carl K wrote: >> Is there a more elegant way of coding this: >> >> x=o.p # save .p >> o.p=0 >> o.m() >> o.p=x # restore .p >> >> seems very push/pop to me - like there should be a way that doesn't >> need a var (x) or the save/set lines should be done in one command. > > With the appropriate context manger, you could write this as:: > > with setting(o, 'p', 2): > o.m() > > Here's the code:: > > >>> from __future__ import with_statement > >>> @contextlib.contextmanager > ... def setting(obj, name, value): > ... old_value = getattr(obj, name) > ... setattr(obj, name, value) > ... try: > ... yield obj > ... finally: > ... setattr(obj, name, old_value) > ... > >>> class C(object): > ... def __init__(self, x): > ... self.x = x > ... def m(self): > ... print self.x > ... > >>> c = C(1) > >>> with setting(c, 'x', 2): > ... c.m() > ... > 2 > >>> print c.x > 1 > > Of course, that just wraps up the same push/pop behavior you're doing > into a context manager.
Thanks. As I was eating lunch I came up with: x,o.p = o.p,0 Which I am pretty sure is just bad :) I need to cut back on the hot sauce. > >> (personally I think .m would better be implemented by passing in a >> parameter, but that isn't my choice.) > > Yep, that's the right answer. You should complain to whoever created > this API. Will do. Something is buggy anyway, so as long as I am commenting... Carl K -- http://mail.python.org/mailman/listinfo/python-list
