Gem #48: Extending Interfaces in Ada 2005

摘要

Ada 2005 introduced the notion of interfaces for designing object classes. While interfaces are extremely convenient for implementing new hierarchies, they can be difficult to extend once they've started to be used. The addition of a new primitive can break all type derivations, as a type has to implement all abstract primitives inherited from its parents. In this Gem, we'll see two ways to overcome this problem, one OOP-generic, and one specific to Ada 2005.