<img src="./images/img01.png" title="" alt="MOGWAI" data-align="center">

MOGWAI - A powerful stack-based RPN scripting engine for .NET

Embeddable, extensible, production-ready. From IoT automation to desktop scripting, one elegant RPN runtime for your .NET apps.

What is MOGWAI?

MOGWAI is a modern implementation of RPN (Reverse Polish Notation) for the .NET ecosystem. Inspired by the legendary HP calculators (HP 28S, HP 48), it brings the elegance and power of stack-based, concatenative programming to your applications — whether you're scripting complex workflows, embedding a runtime in a desktop or mobile app, designing a custom DSL, or automating IoT pipelines.

Key Features

• Stack-Based RPN Syntax - Clean, unambiguous, no operator precedence
• 240+ Built-in Functions - Math, strings, lists, files, HTTP, BLE, and more
• Async/Await Support - Modern asynchronous execution
• IoT Ready - Bluetooth Low Energy, serial ports, GPIO
• Battle-Tested - 10+ years of real-world usage
• Extensible - Easy integration with .NET applications
• Cross-Platform - Windows, Linux, macOS, Android, iOS
• Visual Debugging - MOGWAI STUDIO integration (coming soon)

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The MOGWAI Ecosystem

MOGWAI Runtime (Open Source)

The core scripting engine, available as a NuGet package. Embed MOGWAI in your .NET applications.

• License: Apache 2.0
• Package: MOGWAI on NuGet
• Status: Production ready

MOGWAI CLI (Open Source)

Command-line interface for running MOGWAI scripts and interactive REPL sessions.

• License: Apache 2.0
• Repository: MOGWAI CLI
• Status: Functional

MOGWAI STUDIO (Coming Soon)

Visual IDE for MOGWAI development with debugging, breakpoints, and code editing.

• License: Proprietary (Freemium model)
• Status: In active development
• Features: Visual debugger, syntax highlighting, project management
• Release: TBA

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Quick Start

Installation

Install the MOGWAI runtime via NuGet:

dotnet add package MOGWAI

Hello World

using MOGWAI.Engine;
using MOGWAI.Interfaces;

var engine = new MogwaiEngine("MyApp");
engine.Delegate = this; // Your class implementing IDelegate

var result = await engine.RunAsync(@"
    \"Hello from MOGWAI!\" ?
    2 3 + ?
", debugMode: false);

MOGWAI Language Example

# Variables
42 -> '$answer'
"Hello World" -> '$greeting'

# Functions
to 'square' with [n: .number] do
{
    n n *
}

# Lists
(1 2 3 4 5) foreach 'n' transform { n square } -> '$result'
$result ? # Outputs the list of squares (1 4 9 16 25)

# Records
[name: "MOGWAI", version: "8.0"] -> 'info'

# Conditionals
if (answer 40 >) then
{
    "Answer is greater than 40" ?
}

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Build from Source

Prerequisites

• .NET SDK 9.0 or later
• Git

Clone and Build

# Clone repository
git clone https://github.com/Sydney680928/mogwai.git
cd mogwai

# Restore dependencies
dotnet restore src/MOGWAI/MOGWAI.sln

# Build
dotnet build src/MOGWAI/MOGWAI.sln --configuration Release

# Pack (optional)
dotnet pack src/MOGWAI/MOGWAI.sln --configuration Release

The compiled assembly will be in src/MOGWAI/MOGWAI/bin/Release/net9.0/.

Project Structure

mogwai/
├── src/
│   └── MOGWAI/
│       ├── MOGWAI.sln          # Main solution
│       └── MOGWAI/
│           ├── Engine/         # Core runtime engine
│           ├── Objects/        # MOGWAI object types
│           ├── Primitives/     # Built-in functions (240+ primitives)
│           ├── Interfaces/     # Public interfaces (IDelegate, IPlugin)
│           └── Exceptions/     # Exception types
├── docs/
│   └── EN/
│       ├── MOGWAI_EN.md                      # Language reference
│       ├── MOGWAI_FUNCTIONS_EN.md            # Function reference
│       └── MOGWAI_INTEGRATION_GUIDE_EN.md    # Integration guide
├── images/                     # Screenshots and media
├── LICENSE                     # Apache 2.0 license
├── NOTICE                      # Copyright notice
└── README.md                   # This file

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Documentation

Complete Guides

• Language Reference - Complete MOGWAI language guide
• Function Reference - All 240+ built-in functions
• Integration Guide - How to integrate MOGWAI in your .NET apps

Examples

Examples are available :

• MOGWAI CLI - Command-line interface and REPL
• WinForms Example - Turtle graphics with MOGWAI
• MAUI Example - Cross-platform mobile app
• Blazor Example - Blazor WASM app

Changelog

See CHANGELOG.md for a detailed history of changes.

Latest Release: v8.4.0

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MOGWAI STUDIO (Coming Soon)

MOGWAI STUDIO is a visual IDE for MOGWAI development currently in active development.

Planned Features

• Visual Debugger - Set breakpoints, step through code
• Syntax Highlighting - Color-coded MOGWAI syntax
• Variable Inspector - Examine variables in real-time
• Stack Visualization - See the stack state at any point
• Project Management - Organize scripts and modules
• Network Debugging - Debug remote MOGWAI runtimes
• Code Completion - IntelliSense for MOGWAI functions

Availability

Status: In development
Release Model: Freemium (Free version + Pro version)
Price: Pro version planned at €29 (one-time purchase)
Distribution: Gumroad + installer package

Stay tuned for updates on mogwai.eu.com!

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Use Cases

Industrial IoT Automation

# Read sensor via BLE
"AA:BB:CC:DD:EE:FF" ble.connect -> 'device'
device "temperature" ble.read -> 'temp'

# Control based on value
if (temp 25 >) then
{
    "fan" gpio.on
}

Use Case #1 — Electronic Board Test Bench

Embedded Applications

# WinForms turtle graphics
100 turtle.forward
90 turtle.right
100 turtle.forward
"Square complete!" ?

Blazor WASM Applications

You can test it live on Blazor REPL

Roadmap

Version 8.0 (Released)

• Complete rewrite with namespace organization
• 240+ primitives
• Apache 2.0 open source license
• Published on NuGet
• .NET 9.0 support
• Complete documentation

Version 8.4 (Latest)

• Plugin abstraction layer (MOGWAI.Plugin.Abstractions)
• AOT compatibility (IsAotCompatible)
• Major performance optimizations (O(1) primitive lookup, LINQ removal in hot paths)
• bag primitive
• !A auto-eval sigil
• --> in-place pipeline operator
• Binary data primitives (DATA/BIN families)

Version 8.5 (In Progress)

• MOGWAI STUDIO IDE (beta)
• Enhanced debugging protocol
• Additional examples and documentation

Future Plans

• MOGWAI STUDIO official release
• Community plugins marketplace
• Additional language integrations
• Extended function library

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Contributing

Contributions are welcome! Here's how you can help:

Reporting Issues

Found a bug or have a feature request? Please open an issue on GitHub:

• Bug Reports: Use the bug report template
• Feature Requests: Describe the use case and expected behavior
• Questions: Use GitHub Discussions

Contributing Code

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Make your changes
4. Commit with clear messages (git commit -m 'Add amazing feature')
5. Push to your fork (git push origin feature/amazing-feature)
6. Open a Pull Request

Code Style

• Follow existing code conventions
• Add XML documentation comments for public APIs
• Keep functions focused and well-named

Testing

While we don't have formal unit tests, please ensure:

• Your changes compile without warnings
• Existing examples still work
• Add example scripts demonstrating new features

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Why MOGWAI?

Born from Real Needs

Created in 2015 to simulate Bluetooth Low Energy devices for IoT testing. Over 10 years, MOGWAI evolved into a full-featured scripting language used in industrial automation.

Battle-Tested

• 10+ years of real-world usage - From prototyping to industrial environments
• Thousands of scripts - Executed in field deployments

HP Calculator Heritage

Inspired by the legendary HP 28S and HP 48 calculators, MOGWAI brings RPN elegance to modern software:

• Clear semantics - No operator precedence confusion
• Stack-based - Natural for complex calculations
• Composable - Build complex operations from simple parts

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License

MOGWAI Runtime & CLI

Apache License 2.0

Copyright 2015-2026 Stéphane Sibué

Licensed under the Apache License, Version 2.0 (the "License");
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