Chelis

Chelis is a numerical computing language for code that agents write and people supervise. Tensors carry named dimensions and precision in their type, and a proof stack checks the properties you state.

def portfolio_return(w: tensor[3, f64], r: tensor[3, 1, f64]) -> tensor[f64] = {
  weighted = mul(w, r)
  weighted |> sum(0)
}

In numpy, returns shaped 3 by 1 stretch against three weights into a 3 by 3 grid and the sum comes back as a plausible wrong number. chelis check rejects the same multiply before anything runs. The error from its JSON report:

{"kind":"DimensionMismatch","message":"tensor rank mismatch: 1 dims vs 2 dims","severity":0.8,"span":{"span":"point","offset":94},"span_id":"surf:94..103"}

• Checked before it runs. The compiler checks shapes, precision, effects, and ownership. Dimensions match by name, f32 and f64 do not mix without a cast, I/O appears in a function's effects, and random operations take explicit keys.
• An agent in the loop. chelis check answers in JSON with the error kind and source span, and the same input always gets the same answer. chelis tide mcp gives an agent check, eval, prove, and structural edits as MCP tools.
• Properties you can review. chelis prove checks @property declarations with type checking, an SMT solver, or seeded sampling, and each result names the method behind it. A second checker written in Chelis cross-checks the compiler, and a core calculus of Chelis is mechanized in Lean 4.
• General-purpose numerics. Surf (.ch) is the readable syntax; Deep (.dp) is the canonical form the compiler and agents use. Programs build to C. Shells, installed with Reef, cover numerical methods (Nautilus), dataframes (Coral), and quantitative finance (Shoals).

Install a release toolchain

Chelis releases include chelisup, which installs toolchains and selects the version used by each project. chelisup downloads public releases without a GitHub token. The commands below sign in with gh to find and fetch the latest release.

gh auth login
gh release download --repo Chelis-Lang/chelis --pattern chelisup.sh --output - | sh
# If the bootstrap says ~/.chelis/bin is not on PATH:
export PATH="$HOME/.chelis/bin:$PATH"
release_tag="$(gh release view --repo Chelis-Lang/chelis --json tagName --jq .tagName)"
chelisup install "${release_tag#v}"
chelis --version

The bootstrap script installs chelisup; the next command installs the compiler. The release tag has a leading v, while chelisup install takes the bare X.Y.Z version. For a project with a reef.toml, install the version named by its compiler pin before running chelis reef setup, then run chelis reef build. The install guide explains the project workflow.

Start here

• Chelis Guide: first program, CLI, properties, and Reef.
• Examples: executable Chelis programs.
• Language spec and the canonical project reference.
• Architecture: compiler, evaluator, and code generation.
• Contributor setup, the contribution policy, the maintainer guide, and the agent contract.

License

MIT

Build a native program

chelis build app.ch --output out/
./out/app

build invokes the native compiler and links the runtime carried by this compiler. Definitions-only modules produce static libraries. Sources and headers remain available; --emit-c keeps source-only builds. CPU is the primary acceptance lane; HIP and Metal are prerelease targets with known imperfections. See the backend guide for tool requirements, artifact names, compiler overrides, and library linking.