On 4/14/07, James Stroud <[EMAIL PROTECTED]> wrote: > [EMAIL PROTECTED] wrote: > But, if you have masochistic tendencies and want a lot of overhead in > your programming, you can always bind yourself mercilessly to classes: > > > class C(object): > declared = ['bob', 'carol', 'ted', 'alice'] > def __setattr__(self, anattr, aval): > if anattr not in C.declared: > raise TypeError, "Just can't hook you up, bro." > else: > self.__dict__[anattr] = aval >
You could also do this with __slots__, like: >>> class C(object): ... __slots__ = ['bob','carol','ted','alice'] ... >>> c = C() >>> c.bob = 42 >>> c.bob 42 >>> c.x = 69 Traceback (most recent call last): File "<stdin>", line 1, in ? AttributeError: 'C' object has no attribute 'x' although, I personally have never found the need nor desire to use __slots__ > > E.g.: > > py> class C(object): > ... declared = ['bob', 'carol', 'ted', 'alice'] > ... def __setattr__(self, anattr, aval): > ... if anattr not in C.declared: > ... raise TypeError, "Just can't hook you up, bro." > ... else: > ... self.__dict__[anattr] = aval > ... > py> c = C() > py> c.bob = 42 > py> c.bob > 42 > py> c.x = 69 > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > File "<stdin>", line 5, in __setattr__ > TypeError: Just can't hook you up, bro. > > > Extending this ugliness to type-checking is left as an exercise for the > reader. Using metaclasses for such nonsense is left as an exercise for > metaclass maniacs. > > James > -- > http://mail.python.org/mailman/listinfo/python-list > -- http://mail.python.org/mailman/listinfo/python-list
