Lecture
This lecture covers the concept of class hierarchies and pattern matching in Scala. It starts by explaining the implementation of class hierarchies using case classes and enums. The lecture then delves into the use of pattern matching to simplify data access and manipulation. It also discusses the expansion of function values and calls in Scala, providing a deeper understanding of how functions are treated as objects. The lecture concludes with a practical exercise on implementing an abstract class for non-negative integers and exploring the use of enums for domain modeling tasks.