20.10 Summary

Rust embraces key OOP concepts—methods, encapsulation, and polymorphism—on its own terms:

  • Methods and restricted data access are provided through impl blocks and module visibility rules.
  • Traits offer shared behavior and polymorphism, replacing classical inheritance.
  • Trait objects enable dynamic dispatch, similar to virtual methods, but with runtime overhead and fewer compile-time optimizations.
  • Generics often provide a more performant alternative to dynamic polymorphism by allowing static dispatch and specialization.
  • Enums are ideal for closed sets of types, offering compile-time checks and avoiding vtable overhead.
  • Serialization of trait objects is not straightforward because runtime pointers and vtables cannot be directly persisted.

By combining traits, generics, modules, and composition, Rust allows you to create maintainable, reusable code while avoiding many pitfalls associated with deeply nested class hierarchies.