Systems Lean is the project: Lean 4 with linear/affine ownership and QTT multiplicities 0 / 1 / omega, aimed at freestanding systems products, reached by a meet-in-the-middle bridge between Idris 2 and Lean 4.
The freestanding compiler product of this project is Slake.
(Checkout directory may still be named iso on disk; the project name is Systems Lean.)
Slake is a compiler written in Systems Lean. Focus: freestanding runtimeless C (out/freestanding-c) with memory safety from linear types, no garbage collection on the product wire, and only the minimum Quantitative Type Theory multiplicities (0 / 1 / omega) needed for that path.
Living tip: freestanding product self-host complete and product residual free are both true; host still uses classic Lean Lake. Free is not "Lake is gone," not proof complete, not PROVABLY, not LLVM. Bootstrap status and Open residual: doc/SESSION-HANDOFF.md, RESIDUAL-systems.md. LLVM IR for Rust-native link stays deferred (out/llvm-ir).
Meet-in-the-middle Idris 2 and Lean 4 correspondence feeds Slake -- sides live under src/idris2/ and src/lean4/.
Three languages only for novel work: Idris 2, Lean 4 (including Systems Lean / Slake), and pure Nix flakes (small modules under nix/, not bash-in-Nix). No project Python; shell under script/ is migration debt to shrink. Freestanding C is generated product wire (emit / out), not a fourth source language. Thin just orchestrates only. Policy and language inventory: AGENTS.md, terms: doc/vocabulary.md, goals: doc/goals.md. Spec and proof stay separated; red/green tests stay required.
| Doc | Purpose |
|---|---|
| doc/goals.md | Full goals, non-goals, honesty ladder |
| doc/vocabulary.md | Stable terms (project = Systems Lean; Slake = compiler; tooling terms) |
| doc/architecture.md | Meet-in-the-middle sketch |
| doc/divergence.md | Honest differences and trusted computing bases |
| AGENTS.md | Agent hygiene, isolation, project skills, pure Nix tooling, language inventory (SSoT -- single source of truth) |
| RESIDUAL.md | Living open work for this project |
.agents/skills/ |
Project skill discovery (symlinks; hosts walk this path) |
| Path | Upstream | Role |
|---|---|---|
ref/Idris2 |
Idris2 | QTT / linear side |
ref/lean4 |
Lean 4 | Kernel / elaborator / proof side |
ref/CompCert |
AbsInt CompCert | ccomp source for CompCert-oriented C path |
ref/rust |
rust-lang/rust | Type layout / ABI + LLVM codegen reference (not llvm-project alone) |
Do not treat ref/ as product source. Systems Lean language work and the Slake compiler live in this repository.
Entry maps: doc/idris-entry.md, doc/lean-entry.md, doc/compcert-entry.md, doc/rust-entry.md.
Lean 4 coding-agent workflows ship as a project skill (no global install required for discovery):
| Skill | Discovery path | Body (submodule) |
|---|---|---|
| lean4 | .agents/skills/lean4 |
skills/lean4-skills (cameronfreer/lean4-skills) |
After clone: git submodule update --init --recursive skills/lean4-skills. Policy, overrides, and when to use for residual/plans: AGENTS.md (Project agent skills). Inventory: skills/README.md. Lean entry map: doc/lean-entry.md.
Work here. This repository is Systems Lean. Do not default to other trees for residual or implementation. Escalate off-repo only when a human is explicitly desperate for a specific solution.
.
+-- src/ # Novel product work (not upstream)
| +-- idris2/ # Idris side -- isomorphism / QTT (Quantitative Type Theory) side
| +-- lean4/ # Lean 4 side -- kernel/elaborator-facing novel work
| +-- systems/ # Freestanding Systems Lean + Slake host (min 0/1/omega; no product GC)
+-- out/
| +-- freestanding-c/ # Generated freestanding product wire (release; not hand-authored)
| +-- llvm-ir/ # LLVM IR for Rust-native link (deferred post self-host)
+-- ref/ # Language/compiler upstream (Idris2, lean4, CompCert, rust)
+-- skills/ # Agent skill pack submodules (lean4-skills; not product)
+-- .agents/skills/ # Project skill discovery (symlinks into skills/)
+-- doc/ # Goals, vocabulary, architecture, entry maps
+-- nix/ # Pure Nix tooling modules (hygiene, progress, host/emit gates)
+-- script/ # Process glue only (optional git-hooks/pre-commit -> just check); no mills
+-- justfile # thin orchestration: check | build (product wire; default: list)
+-- flake.nix # Thin wire-up: checks / packages / devShell (no shell-farm apps)
+-- AGENTS.md # Agent policy + skills + tree map + language inventory (SSoT)
+-- RESIDUAL.md # Living open work
Full evolving map: AGENTS.md. Product code never under ref/ or skills/.
Language inventory and freestanding C git policy: AGENTS.md (Three languages only -- single source of truth; do not fork a second inventory here). Terms: doc/vocabulary.md.
Forks: doc/fork-idris.md, doc/fork-lean.md. Coordinator: doc/fork-coordinator.md.
Agent residual loop (not a product map): WATCHER.md.
Meters, hygiene, and host/emit gates are pure Nix under nix/ (not project Python; no shell-farm flake apps). Thin just only orchestrates.
nix develop # elan (Lean/Lake pin manager) + idris2 + just + rg + scc
just # list
just check # CI-identical full suite
just progress # pure Nix meters -> doc/PROGRESS.md
just watch # every 300s: progress-scc + hygiene (just loop)
just build # product freestanding wire (emit + out/freestanding-c)
just out-llvm-ir # deferred (see out/llvm-ir/README.md)Lean elaborator pin is leanprover/lean4:v4.32.0 (src/systems/lean-toolchain, src/lean4/lean-toolchain).
In the dev shell: elan toolchain install "$(tr -d '[:space:]' < src/systems/lean-toolchain)" once.
Workspace checks skip Lake when the pin is not installed (no surprise network download).
Side residuals: RESIDUAL-idris.md, RESIDUAL-lean.md. Coordinator: RESIDUAL.md.
ASCII map: doc/ascii-symbol-map.md. Policy and language inventory: AGENTS.md.
- Our work (everything we commit outside
ref/andskills/): The Unlicense -- public domain dedication. See LICENSES.md. - Author: Hunter "cryptoquick" Beast.
- SPDX for our crates / modules / packages:
Unlicense(Cargo, Lake, Idris, Nix metadata, optional file headers). Details in LICENSES.md. - Submodules under
ref/andskills/: keep their own licenses (Idris 2 BSD-style, Lean 4 Apache-2.0, CompCert non-commercial/AbsInt, Rust Apache-2.0 OR MIT, lean4-skills MIT, ...). Tracked in LICENSES.md.
Active Systems / Slake residual and living tip: doc/SESSION-HANDOFF.md and RESIDUAL.md. Foundation docs and upstream submodules are in place; product work is under src/systems/.