# fastC

> A small systems language with capability-typed I/O, mandatory contracts, and zero executable build scripts — built for the age of agent-generated code. Compiles to portable C11. v1.0 feature-complete; MIT-licensed; Sigstore + SLSA L3 on releases.

fastC is a research project of Skelf-Research. The compiler is written in Rust (1.85+), emits readable C11, and ships eight pre-wired cross-compile targets via `zig cc`. The language is designed around four properties: capability-typed I/O as function arguments (no ambient `fs::read`), mandatory `@requires`/`@ensures` contracts on public APIs with three-tier discharge (syntactic → Z3 → runtime trap), declarative-only package manifests with no executable build scripts, and a compile-time budget enforced in CI.

The honest framing is in [docs/MANIFESTO.md](https://github.com/Skelf-Research/fastc/blob/main/docs/MANIFESTO.md): fastC is not "Rust minus features" — it is the smaller language that combines capability typing, mandatory contracts, no `build.rs`-class scripts, vendored content-hashed deps with cosign keyless + SLSA L3, and one curated answer per domain via `fastc-core`. The wedge is structural answers Rust cannot retrofit without breaking its ecosystem.

## Docs
- [Overview](https://fastC.skelfresearch.com/): tagline, syntax samples, measured numbers, top-level wedge
- [About](https://fastC.skelfresearch.com/about/): the thesis, what we commit to, what we don't commit to
- [Documentation](https://docs.skelfresearch.com/fastc/): full language guide, CLI reference, C interop, getting started

## Comparisons
- [vs Rust](https://fastC.skelfresearch.com/compare/rust/): row-by-row with verdicts
- [vs Zig](https://fastC.skelfresearch.com/compare/zig/): closest in spirit; differs on capabilities + contracts

## Blog
- [What goes wrong when LLMs write C: the recurring bugs](https://fastC.skelfresearch.com/blog/llm-c-recurring-bugs/)
- [Reading fastC: side-by-side syntax with plain C](https://fastC.skelfresearch.com/blog/reading-fastc-vs-c/)
- [Why agent-friendly is a real language design goal](https://fastC.skelfresearch.com/blog/agent-friendly-language-design/)

## Source
- [github.com/Skelf-Research/fastc](https://github.com/Skelf-Research/fastc): MIT, ~270 tests, Cargo workspace