Paco

A general-purpose programming language focused on simplicity, safe concurrency, ownership-based memory safety, strong enums, and pattern matching.

Status: design / bootstrap. There is no working compiler yet — this repo holds the design, the implementation requirements, and the skeleton.

Principles

1. Opinionated, but with freedom — one recommended way, with explicit escape hatches.
2. Visible cost — no hidden allocation, copying, or dynamic behavior.
3. Low mental cost by default — complexity only shows up when you need it.

Where to start

• AGENTS.md — context for AI agents and a language quick-reference.
• docs/design/spec.md — the language specification (the "what").
• docs/implementation/requirements.md — requirements and roadmap (the "how to build").
• docs/design/decisions/ — ADRs: the design decisions and their rationale.
• examples/ — idiomatic programs (also serve as regression tests).

Repository layout

paco/
├── AGENTS.md            # context for AI agents
├── README.md
├── docs/
│   ├── design/          # spec + ADRs (decisions)
│   ├── implementation/  # requirements + roadmap
│   └── grammar/         # tokens and EBNF grammar
├── examples/            # example programs (.paco)
├── tests/conformance/   # tests: should_compile, should_fail, run_output
├── compiler/            # RUST — the compiler
├── runtime/             # RUST (+asm) — scheduler, channels (embedded in binaries)
└── src/                 # PACO — the standard library
    ├── core/            #   Option, Result, fundamental traits
    ├── collections/     #   Vec, Map, Set
    ├── io/              #   files, stdin/stdout
    └── math/            #   numeric / data module

The Rust ↔ Paco boundary: what runs below the language (compiler, runtime) is Rust; what lives inside the language (standard library) is Paco.

Dependencies

Decentralized, version-control-based. A dependency is its source URL pinned to a semantic-version tag; the manifest is paco.mod. There is no central registry.

License

To be defined.