AquaSynth/README.md

# AquaSynth

C# front-end for AquaSynth patch scripts. It parses the AquaSynth patch DSL
into a serializable patch graph, emits Faust `.dsp`, and can ask an installed
Faust compiler to generate backend code such as C#, C++, C, or Rust.

This repo is the C# bridge for AquaSynth/Vortice-land. Rust remains the reference
lab; this project is the tool that lets the engine script Faust without dragging
the AquaSynth-rs crate into the room by the ankle.

## Run

```powershell
dotnet test
```

DX7 reference-render tests use `dexed-py` when a Python with `dexed` and
`numpy` is available. Set `AQUASYNTH_DX7_PYTHON` to that interpreter to force a
specific runtime; otherwise the tests skip the render path and still parse the
vendored public-domain fixture.

ZynAddSubFX is pinned as a GPL test/development reference under
`external/zynaddsubfx`. Initialize it with:

```powershell
git submodule update --init --recursive
```

That source is a parity oracle only. AquaSynth does not ship Zyn code, link it
from `AquaSynth.Dsl`, or treat it as runtime machinery.

## Package Boundary

Downstream consumers should pin this library as an `AquaSynth.Dsl` NuGet
package, not use it as a live project reference. Breaking synth-library work
should happen here freely, then consumers should intentionally update only after
a new package version is packed and tested.

```powershell
dotnet pack src\AquaSynth.Dsl\AquaSynth.Dsl.csproj -c Release
```

The test suite verifies that development fixtures, Python render helpers,
external reference synth sources, and SysEx banks do not ship in
`AquaSynth.Dsl.nupkg`.

## Shape

- `PatchScript.Parse(script)` lowers terse script into `SynthPatch`.
- `FaustEmitter.Emit(patch)` emits Faust source.
- `FaustCompiler.ValidateAsync(source)` compile-checks with Faust when present.
- `FaustCompiler.CompileAsync(source, options)` writes generated backend code.
- `BuiltInScripts.ReferenceScripts()` carries readable SFXR, BFXR-flavored,
  808, FM bell, wobble bass, and advanced layered patches. They are stable
  references for testing and for judging whether the DSL can express useful
  sound designs cleanly.
- `SfxrParams`, `PatchScriptScoring`, `AudioAnalyzer`, and `Presets` carry the
  reusable AquaSynth-rs-side analysis, scoring, SFXR, and preset tools.

Faust `2.85.5` supports `-lang csharp`, so the intended hot path is:

```csharp
var patch = PatchScript.Parse("""
    voice
        wave=saw
        freq=55
        gain=0.2
        sustain=0.5
        decay=0.2
    """);
var export = FaustEmitter.Emit(patch, new FaustExportOptions("bass"));
await FaustCompiler.CompileAsync(
    export.Source,
    new FaustCompileOptions(FaustTargetLanguage.CSharp, "Generated/Bass.cs"));
```

## Status

The current slice covers the modular graph surface needed by the reference
scripts, SFXR atoms, script scoring, audio comparison, presets, Faust emission,
and installed Faust validation. Migration coverage is tracked in
[`docs/migration-checklist.md`](docs/migration-checklist.md), because leaving
important things behind in the old repo would be a very efficient way to become
our own haunted house.

Reference-driven DSL growth is tracked in
[`docs/reference-synth-roadmap.md`](docs/reference-synth-roadmap.md). Agent
handoff state lives in [`state/spine.yaml`](state/spine.yaml).