# logos-tutorial

Tutorial series and reference documentation for building Logos modules.

## Start Here

**New to Logos?** Start with the developer guide -- it walks through creating, building, packaging, and running your first module:

- [Logos Developer Guide](logos-developer-guide.md)

## Next Tutorials

Step-by-step tutorials that build on each other. Each creates a working module you can run.

- **Part 1:** [Wrapping a C Library](tutorial-wrapping-c-library.md) -- build `calc_module`, a core module that wraps a C library (`libcalc`). Covers external library configuration, CMake integration, building, inspecting with `lm`, testing with `logoscore`, and packaging with `nix-bundle-lgx`.

- **Part 2:** [Building a QML UI App](tutorial-qml-ui-app.md) -- build `calc_ui`, a QML-only `ui_qml` module that calls `calc_module` through the `logos.callModule()` bridge. No compilation needed. Scaffold: `nix flake init -t ...#ui-qml`

- **Part 3:** [Building a C++ UI Module (Process-Isolated)](tutorial-cpp-ui-app.md) — build `calc_ui_cpp`, a `ui_qml` module with a C++ backend that runs in a separate `ui-host` process. Define the remote interface in a `.rep` file; the C++ backend inherits from the generated `SimpleSource`; QML accesses it via a typed replica using `logos.module()` and `QtRemoteObjects.watch()`. Scaffold: `nix flake init -t ...#ui-qml-backend`

- **logos-dev-boost:** [Scaffolding Modules with logos-dev-boost](tutorial-dev-boost.md) — use the `logos-dev-boost` CLI to auto-generate modules from C library directories. Wraps libcalc (source-only) and sqlcipher (pre-built `.so`), including integration tests that create encrypted databases. Covers `--type module`, `--type full-app`, and `--lib-dir`.

## Executable Tutorials

Tutorials have YAML specs in `tests/` that can be both **executed** (to verify they work) and used to **generate** the `.md` files. See [docs/spec.md](docs/spec.md) for the full format reference.

```bash
# Run a tutorial end-to-end, writing to a directory you can inspect afterwards
python3 tools/tutorial_runner.py run tests/tutorial-wrapping-c-library.test.yaml \
  --workdir /tmp/my-tutorial-test --verbose

# Run only specific phases (scaffold, files, build, inspect, logoscore)
python3 tools/tutorial_runner.py run tests/tutorial-wrapping-c-library.test.yaml \
  --phase scaffold,files,build --verbose

# Re-run a single phase against a previous build
python3 tools/tutorial_runner.py run tests/tutorial-wrapping-c-library.test.yaml \
  --workdir /tmp/my-tutorial-test --phase inspect --verbose

# Generate the .md tutorial from the YAML spec
python3 tools/tutorial_runner.py generate tests/tutorial-wrapping-c-library.test.yaml

# Pin all GitHub URLs to a specific release tag
python3 tools/tutorial_runner.py run tests/tutorial-wrapping-c-library.test.yaml --release tutorial-v2
python3 tools/tutorial_runner.py generate tests/tutorial-wrapping-c-library.test.yaml --release tutorial-v2
```

The `--workdir` flag lets you point the runner at a directory of your choice — all files, builds, and artifacts end up there so you can inspect or re-use them. Without it, a temp directory is created and deleted after the run (use `--keep-workdir` to preserve it).

The `--release` flag (or the `release` field in the YAML) pins all `{release}` placeholders in GitHub URLs to a git tag, so `github:logos-co/repo{release}#output` becomes `github:logos-co/repo/tutorial-v2#output`. Set it to `""` or omit it for latest.

## Example Modules

Working module source code used by the tutorials:

| Directory | Module | Type | Tutorial |
|-----------|--------|------|----------|
| `logos-calc-module/` | `calc_module` | `core` (wraps libcalc) | Part 1 |
| `logos-calc-ui/` | `calc_ui` | `ui_qml` (QML-only) | Part 2 |
| `logos-calc-ui-cpp/` | `calc_ui_cpp` | `ui_qml` (C++ backend + QML view) | Part 3 |