Macros in Elixir are powerful metaprogramming tools that allow you to write code that generates code at compile time, enhancing the flexibility and expressiveness of the language.

Macros are a distinctive feature of Elixir that enable developers to engage in metaprogramming, allowing them to write code that can generate or transform other code at compile time. This capability can significantly enhance the expressiveness and flexibility of the language, enabling the creation of domain-specific languages (DSLs) or reducing boilerplate code. To define a macro, you use the defmacro keyword, followed by the macro's name and its implementation. When a macro is invoked, it receives its arguments as an abstract syntax tree (AST), which it can manipulate before the code is compiled. This allows for powerful abstractions and optimizations, such as generating multiple function definitions based on patterns or configurations. However, macros should be used judiciously, as they can complicate code readability and maintainability if overused. By leveraging macros, developers can create more reusable and modular components, fostering innovation in how they structure their Elixir applications.