z2js 0.2.1

Z-Machine to JavaScript compiler - convert Infocom-style text adventures to playable web games

z2js - Z-Machine to JavaScript Compiler

A Python compiler that converts Z-machine story files (.z1-.z8) to playable JavaScript that runs in browsers or Node.js.

Features

• Multi-version support: Handles Z-machine versions 1-8
• Browser and Node.js: Generated code works in both environments
• Save/Load: Game state persistence using localStorage (browser) or files (Node.js)
• Interactive HTML UI: Automatically generates a styled HTML wrapper for browser play
• Modular architecture: Clean separation between parser, code generator, and runtime

Installation

pip install z2js

For development or from source, see INSTALL.md.

Usage

Basic compilation

# Compile a Z-machine file to JavaScript
z2js game.z3

# This generates:
# - game.js: The JavaScript runtime and game data
# - game.html: Interactive HTML player interface

Command-line options

# Specify output file
z2js game.z3 -o mygame.js

# Skip HTML generation
z2js game.z3 --no-html

# Verbose output (shows version, serial, etc.)
z2js game.z3 -v

# Show help
z2js --help

Project Structure

z2js/
├── z2js           # Main compiler executable
├── zparser.py     # Z-machine file parser
├── opcodes.py     # Opcode decoder and instruction set
├── jsgen.py       # JavaScript code generator
└── test-output/   # Test compilation outputs

Architecture

Components

1. Parser (zparser.py)

   • Reads Z-machine story files
   • Parses headers, objects, dictionary
   • Decodes Z-strings and packed addresses

2. Opcode Decoder (opcodes.py)

   • Decodes all instruction forms (short, long, variable, extended)
   • Handles version-specific opcodes
   • Tracks operands, store variables, and branch targets

3. JavaScript Generator (jsgen.py)

   • Generates optimized JavaScript runtime
   • Embeds story data as base64
   • Creates complete Z-machine interpreter in JavaScript

Runtime Features

The generated JavaScript runtime includes:

• Memory management: Dynamic and static memory regions
• Stack machine: Call stack and evaluation stack
• Object system: Full object tree with attributes and properties
• I/O system: Text output, keyboard input, save/restore
• Z-string decoder: Handles abbreviations and special characters

Supported Games

The compiler has been tested with:

• Zork I-III
• Planetfall
• Enchanter
• Mini-Zork
• Most Inform 6/7 compiled games

Browser Play

Open the generated HTML file in any modern browser:

# After compilation
open game.html  # macOS
xdg-open game.html  # Linux
start game.html  # Windows

Features in the browser interface:

• Retro terminal styling with green-on-black text
• Command history (arrow keys)
• Save/Load buttons
• Restart functionality
• Responsive design

Node.js Usage

Simple - Just run it:

node game.js

The game will automatically start when you run the file directly!

Advanced - Use as a module:

// Load the generated module
const { createZMachine } = require('./game.js');

// Create and run the Z-machine
const zm = createZMachine();

// Set up I/O callbacks
zm.outputCallback = (text) => process.stdout.write(text);
zm.inputCallback = // ... handle input

// Start the game
zm.run();

Technical Details

Z-Machine Versions

Version	Max Size	Features	Status
1-2	128KB	Basic	✓ Supported
3	128KB	Standard	✓ Supported
4	256KB	Plus	✓ Supported
5	256KB	Advanced	✓ Supported
6	256KB	Graphics	Partial
7	320KB	Extended	Partial
8	512KB	Large	✓ Supported

Opcode Coverage

Currently implements core opcodes for:

• Control flow (call, return, jump, branch)
• Memory access (load, store, loadw, loadb)
• Object manipulation (get/set attributes, insert, remove)
• Text I/O (print, read, output streams)
• Arithmetic and logic operations
• Stack operations (push, pop)
• Game state (save, restore, restart, quit)

Limitations

• Graphics opcodes (V6) are not fully implemented
• Sound effects are stubbed
• Some extended opcodes may not work correctly
• Mouse input not supported

Future Enhancements

• Complete V6 graphics support
• Blorb file support for resources
• Debugger interface
• Optimization passes for generated code
• TypeScript output option

License

This project is for educational purposes. Please respect the copyrights of original game files.

Acknowledgments

Based on the Z-Machine Standards Document v1.1 by Graham Nelson and the work of the Interactive Fiction community.