BrowserSm: Squeak Smalltalk Virtual Machine for Web Browsers

BrowserSm

A Squeak Smalltalk Virtual Machine for Web Browsers

BrowserSm is a JavaScript-based implementation of the Squeak Smalltalk virtual machine that runs standard Squeak images in web browsers. It enables deployment of complete Smalltalk applications — including a full-featured web browser — without requiring browser plugins or external runtimes. The reference application is a web browser implemented entirely in Smalltalk, demonstrating the power of running live Smalltalk environments in the browser.

Key Features

JavaScript-Based VM: Complete Squeak virtual machine implementation running in browsers without plugins
Standard Image Compatibility: Runs unmodified Squeak 6.0+ images with full language support
Live Development Environment: Full Squeak IDE available in browser with inspect, debug, and modify capabilities
Reference Browser Application: Demonstrates VM capabilities with a complete web browser written in Smalltalk
Constitutional Governance: VM development guided by rigorous specifications ensuring correctness and performance
Dual Deployment: Same images run on desktop Squeak VMs and in web browsers via BrowserSm

Architecture Overview

BrowserSm implements a complete Squeak virtual machine in JavaScript, enabling standard Squeak applications to run in web browsers:

The Virtual Machine Layer

JavaScript-based implementation of the complete Squeak VM:

Bytecode Interpreter: Executes standard Squeak bytecodes in JavaScript
Object Memory Management: Implements Spur object format with garbage collection
Primitive Operations: Maps Squeak primitives to browser APIs (DOM, Canvas, WebGL)
Image Format Support: Loads and boots standard Squeak image files
Development Tools: Integrates with browser developer tools for VM debugging

The Smalltalk Application Layer

Standard Squeak images running on the VM:

Complete Squeak Environment: Full IDE, inspector, debugger, and development tools
Reference Browser Application: Web browser implemented entirely in Smalltalk
Live Object System: All objects inspectable and modifiable at runtime
Web Platform Integration: Smalltalk objects mapped to browser APIs
Cross-Platform Compatibility: Same images run on desktop and web VMs

Quick Start

Try the Web Demo

Experience a complete Squeak environment running in your browser: Launch BrowserSm Demo →

Development Setup

# Clone the repository
git clone https://github.com/pauljbernard/browsersm.git
cd browsersm

# Option 1: Load browser application into desktop Squeak
# Open Squeak 6.0 and file in the packages from src/

# Option 2: Run via the JavaScript VM
# Serve the VM and load a Squeak image
python3 -m http.server 8080
# Visit: http://localhost:8080/vm/index.html

Documentation

Getting Started — Installation and first steps
Architecture Guide — Technical overview and design principles
Constitution — Project governance and development principles
User Guide — Using BrowserSm as a web browser
Developer Guide — Contributing and extending BrowserSm
API Reference — Class and method documentation
Examples — Sample code and tutorials

Live Demo

Experience BrowserSm running in your browser: Launch BrowserSm Web Demo →

Project Status

Current Version: 0.9-alpha Constitutional Compliance: ✅ Fully compliant Web Standards Coverage: ~60% (see Implementation Status)

Recent Milestones

✅ Constitutional compliance achieved (Article I-XII)
✅ Smalltalk script runtime implementation
✅ HTML5 parser with error recovery
✅ CSS flexbox layout engine
✅ Morphic-based browser UI
🚧 BSvm JavaScript interpreter (in development)
🚧 WebGL acceleration
🚧 Advanced CSS features

Philosophy

BrowserSm embodies the Smalltalk design principles articulated by Dan Ingalls:

Personal Mastery: Every component is comprehensible and modifiable
Uniform Metaphor: Everything is an object, everything sends messages
Modularity: Clean separation of concerns with well-defined interfaces
Factoring: Common functionality extracted into reusable components
Reactive Principle: All objects can present themselves meaningfully for inspection

This isn’t just another browser implementation — it’s a demonstration that complex systems can be built with simplicity, consistency, and transparency.

Contributing

BrowserSm development is governed by a Constitution that ensures architectural integrity. All contributions must comply with constitutional principles.

Developer Guide — Getting started with development
GitHub Repository — Source code and issue tracking
Specification Documents — Technical specifications and requirements

License

BrowserSm is released under the MIT License. See LICENSE for details.

“Computing should be a reflection of the mind’s desire to explore and understand.” — Alan Kay