Russ <[EMAIL PROTECTED]> wrote: > I recently discovered a bug in one of my programs that surprised me > because I thought Python's dynamic type checking would have > caught it. > > Suppose I have a function that returns an integer, such as > > def numItems: return len(self.items)
Syntax errors (you need parentheses before the colon). > Now I want to do a test like this: > > if object.numItems() > 2: <do something> Attribute error (unless you've set that numItems "function" to be a _method_ of the class of "object" AND added a "self" argument). > But suppose I mistakenly leave off the parentheses: > > if object.numItems > 2: <do something> > > I would have thought that Python would choke on this, but it > doesn't. Apparently, Python converts the operands to a common > type, but that seems risky to me. Is there a good reason for allowing > a function to be compared to an integer? Thanks. It lets you sort a heterogeneous list which may include objects of many types (and no "conversion to a common type" is involved, btw). However, Guido's decided that Python 3.0 will not allow heterogeneous order-comparisons any more (they can't be removed in 2.* without breaking backwards compatibility -- 3.0 is allowed to break backwards compatibility, but 2.* isn't). Alex -- http://mail.python.org/mailman/listinfo/python-list
