# Contributing to ForeignThon

## Project structure
foreignthon/
├── packages/
│   ├── foreignthon/          # core engine + fpy CLI
│   │   ├── src/foreignthon/
│   │   │   ├── cli.py        # fpy commands
│   │   │   ├── transpiler.py # tokenizer-based transpiler
│   │   │   ├── pack.py       # language pack loader
│   │   │   └── errors.py     # bilingual error hook
│   │   └── tests/
│   └── langs/
│       └── es/               # Spanish language pack
│           └── src/foreignthon_es/es.json

## Setting up

```bash
python -m venv .venv && source .venv/bin/activate
pip install -e "packages/foreignthon[dev]"
pip install -e packages/langs/es
```

## Running tests

```bash
pytest packages/foreignthon/tests/ -v
```

## Adding a new language pack

1. Copy `packages/langs/es/` to `packages/langs/<code>/`
2. Rename `foreignthon_es` → `foreignthon_<code>` throughout
3. Fill in `<code>.json` following the same schema as `es.json`
4. Validate it: `fpy pack packages/langs/<code>/src/foreignthon_<code>/<code>.json`
5. Add tests if the language has tricky characters or edge cases
6. Open a PR or publish independently as `foreignthon-<code>` on PyPI

## Language pack schema

Every pack must have these top-level keys:
`meta`, `keywords`, `builtins`, `exceptions`, `error_messages`, `stdlib`

See `packages/langs/es/src/foreignthon_es/es.json` as the reference.

## Code style

```bash
ruff check packages/foreignthon/src
```