Summary

In this chapter, we discussed a number of topics concerning Elixir and metaprogramming.

Typespecs are used as a means for documenting code (with code) such that other programmers (and ourselves) will know at a glance the expected types of certain functions. Typespecs are also a great tool for annotating code, functions, and modules for static analysis, and for finding type issues or other bugs typically unavailable to dynamically-typed languages.

Behaviours can be thought of akin to interfaces from OO languages. They are a means to define modules that will have a set of public functions with specific arity. If the modules adopting a behaviour do not define any or all of the functions from the behaviour, Elixir will raise a compiler warning.

Protocols are a means of performing high-level pattern matching and function dispatching for certain actions. For example, translating types into printable strings requires implementation of the String.Chars protocol for the specific type. This allows...