Outstanding TODOs: - [ ] [Visitor - Programmatic Example](https://github.com/iandinwoodie/cpp-design-patterns-for-humans#programmatic-example-19) - [ ] [Visitor - When To Use](https://github.com/iandinwoodie/cpp-design-patterns-for-humans#when-to-use-19)
