hirrolot/datatype99

Health v2 · maintenance only

Adoption not part of the score

1508 stars · 28 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

A single-header C99 library providing safe algebraic data types (sum types/tagged unions) with exhaustive pattern matching and compile-time introspection, built on the Metalang99 macro metaprogramming library. It requires no external tools and generates predictable data layouts with compile-time type safety.

Use cases

• define sum types in pure C99
• get exhaustive pattern matching in C
• replace error-prone hand-written tagged unions
• derive serialization for C data types
• model ASTs or binary trees in C
• write type-safe variant types without external code generators

When to choose

• you are writing portable standard C99 and want ADTs with compile-time safety
• you want a header-only solution with no external tooling
• you need guaranteed, documented data layout for generated types
• you are building parsers, interpreters, or protocol implementations in C

When to avoid

• your compiler lacks a conforming C99 preprocessor or chokes on heavy macro expansion
• you want runtime reflection or garbage-collected language ergonomics
• your team avoids preprocessor metaprogramming due to compile-time cost or error readability

Facets

library · maturity stable

type-system parser programming-languages developer-tools c cross-platform algebraic-data-types sum-types tagged-unions pattern-matching metaprogramming c99 header-only variant

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