DMN Modeler

Opinionated VS Code extension for editing DMN decision tables and diagrams, with integrated FEEL evaluation targeting Operaton / Camunda 7 workflows.

⚠️ Agent-Developed Software

This project is primarily developed using AI coding agents. While all code is reviewed, please be aware that the development process is largely automated. Use at your own discretion and report any issues you encounter.

Origin

This project is based on the DMN modeler from Miranum IDE by Miragon GmbH. It has since been forked and is now developed independently as part of the Vasara BPM project, with development driven primarily by AI coding agents.

Features

• DMN 1.3 diagram editor with Decision Requirements Diagram (DRD)
• Decision Table editor
• Literal Expression editor
• Properties panel
• Multiple expression language support (FEEL, JUEL, JavaScript, Groovy, Python, JRuby)
• Toggle text editor for raw XML editing
• Evaluation Panel with:
  • Two FEEL engines: feel-scala (Scala.js) and feelin (JavaScript)
  • Single decision evaluation with input forms
  • Batch evaluation support (JSON/CSV)
  • What-if analysis with decision overrides
  • Rule highlighting: Matched rules are visually highlighted in decision tables after evaluation
  • DRD overlay visualization for multi-decision evaluations
  • Step-through animation for decision traces

Development

Prerequisites

This project uses devenv for development environment management.

# Enter the development environment
devenv shell

# Install dependencies
make install

# Build
make build

# Watch for changes (in separate terminals)
make watch-extension
make watch-webview

# Run tests
make test

# Package as .vsix
make package

Important for CI/CD: All make commands should be run inside the devenv shell:

devenv shell -- make install
devenv shell -- make build
devenv shell -- make test

This ensures all required tools (Node.js, Java, sbt, curl, etc.) are available.

Debug

Press F5 in VS Code to launch the Extension Development Host.

License

Apache-2.0