oxurack

Rust crates built with midir, inspired by Eurorack modules for use with hardware and software MIDI devices.

Oxurack reimagines classic analog module designs in the MIDI domain. Instead of control voltages and audio signals, these crates generate and transform MIDI note, velocity, gate, and CC streams -- suitable for driving synthesizers, DAW plugins, or live-coding sessions.

Architecture

The system is organized in four layers:

+------------------------------------------------------------------+
|  Application / REPL / DAW Plugin                                 |
+------------------------------------------------------------------+
|  Rack Orchestration (oxurack)              [ optional ]          |
|  - holds modules, routes cables, drives clock                    |
+------------------------------------------------------------------+
|  Module Crates                             [ standalone ]        |
|  - turingmachine, clock, noise, lfo, sequencer, ...              |
|  - each implements the Module trait                              |
|  - each is independently usable without the rack                 |
+------------------------------------------------------------------+
|  Core (oxurack-core)                                             |
|  - Module trait, Value types, Scale/quantization                 |
|  - BatchGenerator, routing primitives                            |
+------------------------------------------------------------------+

Every module crate stands alone -- you can use the Turing Machine without the rack, the clock without the noise module, etc. The rack is an optional orchestration layer that wires modules together through a cable routing system, driving them from a shared clock.

Design documents live in docs/design/ and cover the system architecture, module catalog, and core infrastructure.

Modules

Available

Crate	Inspired by	Description
turingmachine	Music Thing Modular Turing Machine Mk2	Shift-register randomisation and looping applied to MIDI note/velocity/gate/CC streams. 14 built-in scales, clock dividers, pulse and gate expander outputs.

Planned -- Timing

Crate	Inspired by	Description
clock	Various	Master clock with configurable BPM, swing, division (div2/4/8) and multiplication (x2/x3) outputs.
euclidean	Euclidean rhythm generators	Bjorklund's algorithm mapped to MIDI triggers and gates.

Planned -- Modulation

Crate	Inspired by	Description
noise	Noise / S&H modules	Random value generation: uniform, Gaussian, Perlin, and Simplex noise algorithms.
lfo	LFO modules	Low-frequency oscillator with sine, triangle, square, saw, and random waveforms. Free-running or tempo-synced.

Planned -- Transformation

Crate	Inspired by	Description
quantizer	Pitch quantizers	Standalone scale quantizer for external MIDI streams.
range	Attenuverters / scalers	Maps values from one range to another (e.g., noise 0--127 to velocity 60--100).
sample-hold	Sample & Hold modules	Captures input value on trigger, holds until next trigger.

Planned -- Sequencing

Crate	Inspired by	Description
sequencer	Classic step sequencers	Step sequencer with per-step note, velocity, gate length, probability, and ratcheting.
arpeggiator	Arp modules	MIDI arpeggiator with classic modes (up, down, up-down, random, order) and octave range.

Planned -- Output

Crate	Inspired by	Description
midi-output	Eurorack output modules	Generic MIDI output module: converts value streams to Note On/Off and CC messages.

Planned -- Infrastructure

Crate	Description
oxurack-core	Module trait, Value types, Scale/quantization, BatchGenerator, routing primitives.
oxurack	Rack orchestration: holds modules, manages cables, drives the tick cycle.

Quick start

use turingmachine::{TuringMachine, Scale};

let mut tm = TuringMachine::with_seed(42);
tm.set_scale(Scale::pentatonic_minor());
tm.set_length(8);
tm.set_write(0.8);

for _ in 0..16 {
    let out = tm.tick();
    if out.gate {
        println!("note={} vel={}", out.note.unwrap(), out.velocity.unwrap());
    }
}

See the turingmachine README for the full API, signal chain diagram, and MIDI I/O examples.

Workspace layout

oxurack/
├── Cargo.toml              # Workspace root
├── crates/
│   ├── oxurack-core/       # Core traits and types (planned)
│   ├── turingmachine/      # MIDI Turing Machine Mk2
│   └── ...                 # Future module crates
└── docs/
    └── design/             # Architecture and module design documents

Features

Each crate may expose optional Cargo features:

Feature	Description
midi-io	Real-time MIDI port I/O via midir.
serde	Serialize / Deserialize on public types.

Building

make build          # debug build
make test           # run all tests
make check          # build + lint + test
make docs           # generate API docs

License

MIT