>> I have two classes that both inherit from two other classes which both >> inherit from a single class. The two children have two almost >> identical methods: >> >> class grandparent( object ): >> def meth( self ): >> # do something >> >> class parent1( grandparent ): >> def meth( self ): >> # do something p1 >> super( parent1, self ).meth( ) >> >> class parent2( grandparent ): >> def meth( self ): >> # do something p2 >> super( parent2, self ).meth( ) >> >> class child1( parent1 ): >> def meth( self ): >> # do something c >> super( parent1, self ).meth( ) # I want to invoke meth on >> grandparent > > If so, it might be better to explicitly call grandparent.meth (passing > self as first argument). But this is an obvious design smell IMHO. What > you have is : > > def meth(self): > do_something_more_or_less_specific > call_granparent > > Looks like a candidate for a template method. Since you don't have hand > on Grandparent, the simplest would be to add an additional base class, ie: > > > class Abstract(Grandparent): > def do_something(self): > raise NotImplementedError > > def meth(self): > self.do_something() > super(Abstract, self).meth() > > > class Parent1(Abstract): > def do_something(self): > # do something p1 > > class Parent2(Abstract): > def do_something(self): > # do something p2 > > > Now you're problem is to factor out do_something() for Child1 and > Child2. The solution is quite simple : just define it outside the class > statements, and adds it afterward: > > def do_something_children(self): > # code here > > class Child1(Parent1): > # code here > > Child1.do_something = do_something_children > > class Child2(Parent2): > # code here > > Child2.do_something = do_something_children
Thanks, this was very helpful. Also, thanks Duncan, your simple suggestion was helpful too to just call the grandparent directly (without super). Cheers, Daniel -- Psss, psss, put it down! - http://www.cafepress.com/putitdown -- http://mail.python.org/mailman/listinfo/python-list
