Epic 8: Project modernization

[aalhour]

Epic 8: Project modernization

Goal: bring tooling, layout, and dependencies to current Python best practices.

• Switch to src/ layout — move pycoolc/ into src/pycoolc/. Prevents accidental imports of the source tree instead of the installed package. Update pyproject.toml, Makefile, CI, and test imports.
• Replace PLY with a maintained parser library — PLY's last release was 2018. Candidates: lark (Earley/LALR, modern API, maintained), sly (PLY author's successor, similar API), or hand-written recursive descent. Biggest change in the project — lexer and parser rewrite, all tests must pass.
• Switch build backend to hatchling — drop setuptools + MANIFEST.in + *.egg-info. Hatch handles discovery, versioning, and sdist inclusion natively from pyproject.toml.
• Remove MANIFEST.in — becomes unnecessary after switching to hatchling or equivalent.
• Delete committed PLY cache files — lextab.py, yacctab.py, parsetab.py at repo root and in examples/. These are generated artifacts. Ensure .gitignore covers them and PLY writes to a build/temp dir.
• Adopt uv for dependency management — replace pip + venv with uv for 10-100x faster installs. Add uv.lock for reproducible environments. Update Makefile venv target.
• Replace Makefile with just or hatch scripts — optional but cleaner. just has simpler syntax, better cross-platform support, and no tab sensitivity.
• Add dependency lockfile — uv.lock or pdm.lock for reproducible CI and dev environments. Pin exact versions for dev deps.