Re: some abstract base class dont need vtbl?

Runtime polymorphism isn't what im looking for. I think this other type
of inheritance is the most useful type of all. Just to make clear what
I mean. In java the keyword interface is heavily used. In c++ we do it
by abstract base classes. By publicly inheriting these kinds of classes
we only inherit the interface, and no implementation. (To reuse any
implementation it is considered better to use aggregation or protected
inheritance anyway). We use objects thru their abstract interface and
we only commit to the smallest interface we can. As in;

//Pseudo code..
Class Phil : public WorkerABI, public BeerDrinkerABI {...}
Class Joe : public WorkerABI, public BeerDrinkerABI {...}
....
If(!weekend) {
WorkerAbstarctBase aPtr1 * = new Phil();
aPtr1.work();
aPtr1 = new Joe();
aPtr1.work();
}else {
BeerDrinkerAbstarctBase aPtr1 * = GetRandomBeerDrinker();
aPtr1.drink();
}

Well that might be a bad example but I need it that to answer your
question: "How can you enforce a common interface on a family of
classes by deriving them from an empty base class"

Well any class (Joe or Phil) that want to belong to the family of
workers or beer drinkers has to publicly derive from the abstract base
WorkerABI or BeerDrinkerABI. If it didn't the above code would not
compile. That's because I use the object by an abstract base class
pointer. That is how I can enforce the interface of object of the same
family.

I hope that made some sense.

Cheers /Petke

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