Metaprogramming and Macros

This section covers the part of Scala that lets code participate in code generation and compile-time transformation. The key distinction is historical as well as technical: Scala 2 macros and Scala 3 metaprogramming solve related problems, but they differ significantly in ergonomics, tooling, and maintainability.

Read these pages if you work on libraries, code generation, DSLs, or compile-time validation and need to understand where metaprogramming helps versus where plain types, inline methods, or ordinary runtime code are enough. Most application code should use metaprogramming sparingly.

In this section

• Metaprogramming in Scala 2: Mastering Compile-Time Code Generation with Macros
  Explore Scala 2 metaprogramming with macros, quasiquotes, and reflection, especially as legacy technology you may still need to understand, maintain, or migrate.
• Mastering Metaprogramming in Scala 3: Inline Functions, Macros, and More
  Explore Scala 3 metaprogramming with inline methods, quotes, splices, and compile-time techniques, focusing on where they improve API design and where they add unnecessary complexity.