Macrocontaining

Macrocontaining is a term used in metaprogramming to describe a pattern in which code that generates code is wrapped inside a containment construct, such as a macro container or macro module. The container provides a namespace and a boundary for macro expansion, allowing related macros to be bundled together and to interact in a controlled way. The goal is to improve modularity, reuse, and safety in macro libraries by preventing leakage of internal identifiers and by enabling predictable composition of macros.

Mechanism. In languages that support hygienic macros, macrocontaining relies on hygiene rules to ensure identifiers introduced by a macro do not clash with surrounding code. The container can expose a defined surface of macros while concealing internal helpers. Nested containers may be used to compose macros, with inner containers generating code that remains valid within the outer context.

Applications and challenges. Macrocontaining is useful for building large macro libraries or embedded domain-specific languages, providing modular development and tooling support. Its use can complicate the macro system and may require language features for module-scoped macro names, explicit import/export semantics, or tooling that understands container boundaries.

See also. Macros, hygienic macros, macro hygiene, macro systems, metaprogramming.