Macros

Nitpick macros are compile-time code rewriting rules. A macro invocation is replaced by its expanded body before type-checking and code generation.

Contents

• basic.md — Declaring and invoking macros
• hygiene.md — Variable isolation and gensym
• recursive.md — Recursive macros and the depth guard
• variadic.md — Variadic macros (..?params)
• code_gen.md — Statement-position and code-generating macros
• complex_codegen.md — Multi-decl emission, struct/impl splices, template-literal hygiene (ARIA-061, #caller(NAME))
• builtins.md — Built-in macros: assert!, todo!, unreachable!, cfg!
• debug.md — Debugging macros with --expand-macros

Overview

// declare a macro
macro:double = (x) {
    x + x;
};

// invoke it
int32:result = double!(10i32);   // expands to: 10 + 10

Macros differ from functions:

When to Use Macros

• Generating repetitive code patterns
• Compile-time assertions (assert!, todo!, unreachable!)
• Platform-conditional code (cfg!)
• Zero-cost abstractions that would otherwise require runtime overhead