Onda

CLI and editor tools

Use onda to check and play programs. If you have not installed it yet, follow Getting started. Run onda --help for all commands and options.

The commands below use files from the included examples. Replace the example path with your own .onda, .on, or .ondaproject file when working on a program.

Real-time playback

Open a program in Onda Run:

onda run examples/basic/sine.onda

Onda reloads the program when you save changes to its source files. Projects also reload when you change their project file or buffer assets.

Run onda without a filename to open the file picker. Use --sample-rate, --block-size, --input-device, --output-device, and --theme to choose playback settings.

Play with MIDI

Programs with a supported note_on event show a piano and MIDI input selector. Choose Computer Keyboard to play with A W S E D F T G Y H U J K O L P, or play the piano with a pointer or touch. Select a connected MIDI device to use a hardware keyboard.

The browser playground also has a piano and computer-keyboard input. In browsers that support Web MIDI, choose Connect MIDI device… to request access to hardware.

For a ready-to-play instrument, open a MIDI example. To play Onda inside a DAW, use the Onda VST3 plugin: OndaSynth hosts instruments and OndaFX hosts effects. A DAW supplies tempo and transport inputs through the plug-in; those inputs are inactive in standalone playback.

Play without a window

Use onda run play for command-line playback. Set a duration or keep playing until you stop it:

onda run play examples/basic/sine.onda --dur 2
onda run play examples/basic/sine.onda --forever --set freq=220

Use --set name=value to choose parameter values. To connect a MIDI input, pass its exact device name:

onda run play examples/plugins/instruments/poly_saw.onda \
  --forever --midi-input-device "Your MIDI Device"

Supply samples and other buffers

For your own program with a declared clip buffer, bind a WAV or .ondabuffer file by name:

onda run play my-sampler.onda --buffer clip=sample.wav

For a buffer array, select a slot with a quoted name such as --buffer 'bank[3]=snare.ondabuffer'. Unbound buffers read as zero and discard writes, so missing bindings do not prevent playback.

To save sources and assets together, see Working with projects.

WAV export

If you need an audio file, export a fixed duration from the command line:

onda run render examples/basic/sine.onda --output sine.wav --dur 5

--dur is the duration in seconds. Parameter and buffer overrides work as they do for command-line playback.

Compile and inspect

Check a program for syntax and semantic errors:

onda compile examples/basic/sine.onda

To inspect a graph or generated LLVM IR:

onda compile examples/feedback/cybernetic_feedback_graph.onda --dump-graph
onda compile examples/basic/sine.onda --emit llvm-ir

To compile a native object for use in another application:

onda compile examples/basic/sine.onda --emit obj

Use --target-spec with a target preset when compiling for another platform:

onda compile examples/basic/sine.onda --target-spec ./targets/arm64.toml --emit obj

The Processor API explains how to link and host the resulting object.

Editor support

VS Code

Install the Onda VS Code extension for .onda and .on files, diagnostics, completion, hover, signature help, and go-to-definition. The extension bundles the native compiler; you can select an external compiler in its settings. Run Onda: Run to open the program inside the editor.

Neovim

The Onda Neovim plugin sets up filetype detection and the language server. Use :OndaRunFile to open the current program in Onda Run.

Other editors and tools

Configure a language-server client to start onda lsp over standard input and output. It provides diagnostics, completion, hover, signature help, navigation, document symbols, and semantic highlighting.

To run analysis once from the command line:

onda daemon diagnose examples/basic/sine.onda

Tool integrations can use onda daemon stdio for the daemon’s JSON control interface.

Compile WebAssembly

Install the WebAssembly compiler with Node.js 20 or newer:

npm install @onda-lang/wasm-compiler

If you downloaded a package tarball from a release, install that file instead, replacing X.Y.Z with the downloaded version:

npm install ./onda-lang-wasm-compiler-X.Y.Z.tgz

Then compile a source file:

npx onda-wasm compile examples/basic/sine.onda \
  --root . \
  --output ./sine.wasm

This writes sine.wasm and its matching sine.onda.json descriptor. Compilation does not require LLVM, Rust, or a Wasm linker after the package is installed. See the Web API to compile inside an application or play an artifact through Web Audio.

Embed Onda in an application

  • C API — compile source and run it through libonda.
  • Processor API — link and call a compiled processor directly.
  • Web API — compile and play programs with JavaScript and WebAssembly.