getting-started.md

Getting Started

This is the shortest path to a real Molt install and first successful run.

Prerequisites

• Python 3.12+
• Rust toolchain
• uv
• A C toolchain (clang on macOS/Linux, MSVC or clang on Windows)

Platform details and pitfalls live in:

• README.md
• DEVELOPER_GUIDE.md
• OPERATIONS.md

Install

Package install

• Homebrew / installer / packaging paths: ../packaging/README.md

Local repo workflow

uv sync --group dev --python 3.12
./.venv/bin/molt doctor --json

Verify The Toolchain

molt doctor --json

Expected: JSON output with exit code 0.

Build And Run Hello World

uv run --python 3.12 python3 -m molt.cli build examples/hello.py
./hello_molt

You can also use the run wrapper directly:

uv run --python 3.12 python3 -m molt.cli run examples/hello.py

Compare Against CPython

uv run --python 3.12 python3 -m molt.cli compare examples/hello.py

Benchmark A Script

uv run --python 3.12 python3 -m molt.cli bench --script examples/hello.py

Common Pitfalls

• macOS arm64 + Python 3.14: uv-managed 3.14 can hang; use system python3.14 or stay on 3.12/3.13.
• WASM linked builds require wasm-ld and wasm-tools.
• After changing pyproject.toml or dependency groups, rerun uv sync so the editable molt install in .venv stays current.

Where To Go Next

• Current state: spec/STATUS.md
• Roadmap: ../ROADMAP.md
• Benchmarking: BENCHMARKING.md
• Developer guide: DEVELOPER_GUIDE.md