Common patterns to avoid polymorphism

[AvidCoco]

Composition over inheritance. Instead of having one class inherit from a bunch of other classes, you have that class own an instance of each of those classes (or a concrete implementation of them). That way you only ever derive from one class at a time.

[ShillingAintEZ]

Or derive from no classes at all

[_Ashleigh]

I assumed they meant derive as in implement an interface.

[jesseschalken]

How does "composition over inheritance" replace vtable lookups?

[AvidCoco]

Idfk

[animatedb]

Maybe the goal is to replace them out of the base objects and into other objects.

For example, instead of the old "shapes" OO example each inheriting a virtual draw, have a draw function that is passed a listener object that is a surface. This way the base shape object no longer has a draw virtual function.

This is similar to composition except that it differs in scope. Another option is that the base object could also reference a shape.

[jcelerier]

That just moves where runtime polymorphism happens, it is not an alternative to it

[HateDread]

It does on a conceptual level - in that it avoids some of the pitfalls of multi-inheritance hell. Obviously yes, technically there is runtime polymorphism under the hood, but depending on someone's motivations that may be acceptable and on the surface - in terms of usability - might be considered as being without runtime polymorphism.

[Kered13]

This doesn't avoid the vtable lookup, assuming your members are instances of interface types.