16 Macros

A macro is a syntactic form with an associated transformer that expands the original form into existing forms. To put it another way, a macro is an extension to the Racket compiler. Most of the syntactic forms of racket/base and racket are actually macros that expand into a small set of core constructs.

Like many languages, Racket provides pattern-based macros that make simple transformations easy to implement and reliable to use. Racket also supports arbitrary macro transformers that are implemented in Racket—or in a macro-extended variant of Racket.

(For a bottom-up introduction of Racket macro, you may refer to: Fear of Macros)

    16.1 Pattern-Based Macros

      16.1.1 define-syntax-rule

      16.1.2 Lexical Scope

      16.1.3 define-syntax and syntax-rules

      16.1.4 Matching Sequences

      16.1.5 Identifier Macros

      16.1.6 set! Transformers

      16.1.7 Macro-Generating Macros

      16.1.8 Extended Example: Call-by-Reference Functions

    16.2 General Macro Transformers

      16.2.1 Syntax Objects

      16.2.2 Macro Transformer Procedures

      16.2.3 Mixing Patterns and Expressions: syntax-case

      16.2.4 with-syntax and generate-temporaries

      16.2.5 Compile and Run-Time Phases

      16.2.6 General Phase Levels Phases and Bindings Phases and Modules

      16.2.7 Syntax Taints