Hopplänk

Hopplänk is a term used in the context of object-oriented programming, particularly in languages like C++ and Java. It refers to a technique where a method call is dynamically resolved at runtime rather than being fixed at compile time. This dynamic resolution is a fundamental aspect of polymorphism, allowing a program to execute the appropriate method based on the actual type of an object at the time of the call.

The concept of hopplänk is often implemented using virtual tables, also known as vtables. When a class declares virtual methods, the compiler typically creates a vtable for that class. This vtable is an array of function pointers, where each entry points to the implementation of a virtual method for that specific class. When a virtual method is called on an object, the program uses the object's vptr (virtual pointer), which points to the object's vtable, to find the correct method to execute. This indirection allows for flexibility, as different subclasses can override virtual methods, and the correct implementation will be invoked dynamically.

Hopplänk is crucial for achieving runtime polymorphism, enabling behaviors to be extended and modified without altering existing code. It is a cornerstone of object-oriented design, supporting concepts like inheritance and abstract classes, and is essential for building flexible and extensible software systems. Understanding hopplänk is key to grasping how object-oriented languages manage method dispatch and achieve dynamic behavior.