# Rumoca
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> **Note:** Rumoca is in active development. APIs may change between releases.
A Modelica compiler written in Rust. Rumoca parses Modelica source files and exports a [DAE IR](https://github.com/CogniPilot/modelica_ir) (a superset of [Base Modelica](https://github.com/modelica/ModelicaSpecification/blob/MCP/0031/RationaleMCP/0031/ReadMe.md) supporting both implicit and explicit model serialization). The IR is consumed by [Cyecca](https://github.com/cognipilot/cyecca) for model simulation, analysis, and Python library integration with CasADi, SymPy, JAX, and other backends.
Future export targets include [Base Modelica (MCP-0031)](https://github.com/modelica/ModelicaSpecification/blob/MCP/0031/RationaleMCP/0031/ReadMe.md) and [eFMI/GALEC](https://www.efmi-standard.org/).
## Tools
| `rumoca` | Main compiler - parses Modelica and exports DAE IR (JSON) |
| `rumoca-fmt` | Code formatter for Modelica files (like `rustfmt`) |
| `rumoca-lsp` | Language Server Protocol server for editor integration |
| **VSCode Extension** | Full IDE support via the [Rumoca Modelica](https://marketplace.visualstudio.com/items?itemName=JamesGoppert.rumoca-modelica) extension |
## Installation
### Compiler and Formatter
```bash
cargo install rumoca
```
### VSCode Extension
Search for "Rumoca Modelica" in the VSCode Extensions marketplace, or install from the [marketplace page](https://marketplace.visualstudio.com/items?itemName=JamesGoppert.rumoca-modelica).
The extension includes bundled LSP binaries for all platforms - no additional setup required.
**Features:**
- Syntax highlighting
- Real-time diagnostics
- Autocomplete for keywords, built-in functions, and class members
- Go to definition / Find references
- Document symbols and outline
- Code formatting
- Hover information
- Signature help
- Code folding
- Inlay hints
- Code lens with reference counts
## Quick Start
### Compile to DAE IR (JSON)
```bash
rumoca model.mo --json > model.json
```
### Format Modelica Files
```bash
# Format all .mo files in current directory
rumoca-fmt
# Check formatting (CI mode)
rumoca-fmt --check
# Format specific files
rumoca-fmt model.mo library.mo
# Use 4-space indentation
rumoca-fmt --config indent_size=4
```
### Library Usage
```toml
[dependencies]
rumoca = "0.7"
```
```rust
use rumoca::Compiler;
fn main() -> anyhow::Result<()> {
let result = Compiler::new()
.model("MyModel")
.compile_file("model.mo")?;
// Export to DAE IR (JSON)
let json = result.to_json()?;
println!("{}", json);
Ok(())
}
```
### Use with Cyecca
```bash
rumoca model.mo --json > model.json
```
```python
from cyecca.io.rumoca import import_rumoca
model = import_rumoca('model.json')
# Use model for simulation, analysis, code generation, etc.
```
### Custom Code Generation with Templates
Rumoca supports [MiniJinja](https://docs.rs/minijinja/) templates for custom code generation:
```bash
# Generate CasADi Python code
rumoca model.mo -m MyModel --template-file templates/examples/casadi.jinja > model.py
# Generate SymPy code
rumoca model.mo -m MyModel --template-file templates/examples/sympy.jinja > model.py
```
The DAE structure is passed to templates as the `dae` variable. Example template:
```jinja
# Generated from {{ dae.model_name }}
{% endfor %}
```
See [`templates/examples/`](templates/examples/) for complete template examples (CasADi, SymPy, Base Modelica).
## Modelica Language Support
### Fully Supported
- **Class definitions**: `model`, `class`, `block`, `connector`, `record`, `type`, `package`, `function`
- **Components**: Declarations with modifications, array subscripts
- **Inheritance**: `extends` clause with recursive resolution
- **Equations**: Simple, connect, if, for, when equations
- **Algorithms**: Assignment, if, for, while, when statements
- **Expressions**: Binary/unary operators, function calls, if-expressions, arrays
- **Type prefixes**: `flow`, `stream`, `discrete`, `parameter`, `constant`, `input`, `output`
- **Modifications**: Component and class modifications
- **Packages**: Nested packages, `package.mo`/`package.order` directory structure, MODELICAPATH
- **Imports**: Qualified, renamed, unqualified (`.*`), selective (`{a,b}`)
- **Functions**: Single and multi-output functions, tuple equations `(a,b) = func()`
- **Built-in operators**: `der()`, `pre()`, `reinit()`, `time`, trig functions, array functions
- **Event functions**: `noEvent`, `smooth`, `sample`, `edge`, `change`, `initial`, `terminal`
- **Annotations**: Parsed and exported to JSON on components
### Partially Supported
| Connect equations | Flow/potential semantics implemented; `stream` not yet supported |
| External functions | `external` keyword recognized; no linking |
### Not Yet Implemented
| Stream connectors | `inStream`, `actualStream` operators |
| Inner/outer | Keywords recognized; lookup not implemented |
| Redeclarations | `redeclare`, `replaceable` parsed only |
| Overloaded operators | `operator` class prefix recognized only |
| State machines | Synchronous language elements (Ch. 17) |
| Expandable connectors | Dynamic connector sizing |
| Overconstrained connectors | `Connections.root`, `branch`, etc. |
## Architecture
```
Modelica Source -> Parse -> Flatten -> BLT -> DAE -> DAE IR (JSON)
(AST) (Flat) (Match) (DAE)
|
Cyecca
|
CasADi/SymPy/JAX/etc.
```
**Structural Analysis:**
- **Hopcroft-Karp matching** (O(E√V)) for equation-variable assignment
- **Tarjan's SCC algorithm** for topological ordering and algebraic loop detection
- **Pantelides algorithm** for DAE index reduction (detects high-index systems)
- **Tearing** for algebraic loops (reduces nonlinear system size)
## Development
```bash
# Build
cargo build --release
# Run tests
cargo test --all-features
# Check formatting
cargo fmt --check
rumoca-fmt --check
# Lint
cargo clippy --all-features
```
## Contributing
Contributions welcome! See [CONTRIBUTING.md](CONTRIBUTING.md) for guidelines.
## License
Apache-2.0 ([LICENSE](LICENSE))
## Citation
```bibtex
@inproceedings{condie2025rumoca,
title={Rumoca: Towards a Translator from Modelica to Algebraic Modeling Languages},
author={Condie, Micah and Woodbury, Abigaile and Goppert, James and Andersson, Joel},
booktitle={Modelica Conferences},
pages={1009--1016},
year={2025}
}
```
## See Also
- [Modelica IR](https://github.com/CogniPilot/modelica_ir) - DAE IR specification
- [Cyecca](https://github.com/cognipilot/cyecca) - Model simulation, analysis, and code generation
- [Base Modelica (MCP-0031)](https://github.com/modelica/ModelicaSpecification/blob/MCP/0031/RationaleMCP/0031/ReadMe.md) - Planned export target
- [eFMI/GALEC](https://www.efmi-standard.org/) - Planned export target
- [Modelica Language](https://www.modelica.org/)