Getting started — tools¶

You need a C++ compiler, CMake, Ninja, and LLVM 22 once. After that, building Li is one command.

macOS¶

brew install llvm@22 cmake ninja
export LLVM_DIR="$(brew --prefix llvm@22)/lib/cmake/llvm"
export CC=clang CXX=clang++
./scripts/build.sh
./build/compiler/lic/lic --version

Linux (Ubuntu 24.04+)¶

sudo apt-get install cmake ninja-build clang-22 llvm-22-dev lld-22
export LLVM_DIR=/usr/lib/llvm-22/lib/cmake/llvm
export CC=clang-22 CXX=clang++-22
./scripts/build.sh

If clang-22 is not found, use apt.llvm.org:

wget -O /tmp/llvm.sh https://apt.llvm.org/llvm.sh
chmod +x /tmp/llvm.sh
sudo /tmp/llvm.sh 22
sudo apt-get install -y clang-22 llvm-22-dev lld-22

Linux (Debian 12 bookworm)¶

Debian main repos do not ship LLVM 22; use apt.llvm.org:

sudo apt-get install -y cmake ninja-build wget gnupg zlib1g-dev libzstd-dev python3
wget -O /tmp/llvm.sh https://apt.llvm.org/llvm.sh
chmod +x /tmp/llvm.sh
sudo /tmp/llvm.sh 22
sudo apt-get install -y clang-22 llvm-22-dev lld-22
export LLVM_DIR=/usr/lib/llvm-22/lib/cmake/llvm
export CC=clang-22 CXX=clang++-22
./scripts/build.sh

Or ./scripts/build.sh after export LLVM_DIR=... — it auto-detects via scripts/llvm-env.sh.

Cloud Agent VMs: use cloud-agent-vm.md — bash scripts/cloud-vm-bootstrap.sh.

Dedicated dev box (e.g. engine): use the idempotent script and agent-oriented guide — devbox Li development.

sudo bash scripts/setup-li-devbox.sh --full

Windows¶

Use the GitHub Actions recipe as a reference: LLVM 22 via Chocolatey, then cmake -B build with LLVM_DIR pointing at the install.

Lean 4 (proof gate — optional for quick builds, required for full CI)¶

bash /home/s4il0r/Documents/Cursor/li-langverse/lic/scripts/ci-install-lean.sh
export PATH="$HOME/.elan/bin:$PATH"
cd /home/s4il0r/Documents/Cursor/li-langverse/lic/docs/semantics && lake build

Without lake, lic build still runs but skips semantics verification (see provability-gaps.md).

Your first build¶

./build/compiler/lic/lic build examples/hello.li -o hello --release
./hello

Commands you will use¶

Command	What it does
`lic parse file.li`	Is the syntax OK?
`lic check file.li`	Syntax + types (quick, for the editor)
`lic build file.li -o app`	Full pipeline → runnable program
`lic build file.li -o app --release`	Optimized native binary
`lic build file.li -o app --threads=8`	Hint OpenMP to use 8 threads (when parallel code is present)

lic check is for speed while you type. lic build is the real gate when you want a program you trust.

Run the project’s tests¶

./scripts/ci.sh

That builds Li, runs security checks, and runs the full li-tests suite.

Next: Hello world in depth.