In this appendix, I would like to introduce decorators, another topic that allows us to express solutions to cross-cutting functionalities elegantly. Decorators are useful for parameter checks, for example, and are used primarily in this book for advanced recursion topics.
Decorators allow you to add already existing functionality to new functionality transparently, without extensions in the implementation of a function itself. Although writing decorators is pretty straightforward, there are a few specifics to keep in ...
