Understanding Elixir Macros: The Role of defmacro and require

This article is the third part of a series that explores Elixir macros, explaining their significance and usage. It begins with a recap of previous parts, where a basic test harness was created and the limitations of using functions for assertions were demonstrated. The article then introduces macros in Elixir, defined using defmacro, highlighting that their evaluation occurs at compile time and that they work with quoted expressions. An example of rewriting an assertion function as a macro is provided, revealing how macros can transform code before execution. The author emphasizes the compile-time nature of macros and discusses important considerations, such as the necessity of requiring macros before invoking them. The article concludes by hinting at further sophisticated developments in upcoming installments of the series, maintaining a clear focus on enhancing the reader's understanding of macros in Elixir.