two9a / mcresc

An interactive debugger for Mornington Crescent, written in ES2015

Mornington Crescent Interactive Debugger

Watch the execution of Mornington Crescent programs as they traverse the London Tube network, pause and step through syntax-highlighted code.

This project contains two main components:

• The Mornington Crescent interpreter and debugging renderer;
• A module for directly interacting with the Tube map SVG, as provided by Transport for London.

Requirements

This project is written in vanilla ES2015 with no external dependencies, and has been tested as running directly in Chromium 51 and Firefox 48; other browsers may have issues interpreting the syntax.

Known Issues

• The TfL Tube map denotes stations with a three-letter code as part of a longer ID; the three-letter codes for Wood Lane (on the Circle line) and Woolwich Arsenal (on the DLR) are the same, so the syntax highlighter may refer to one as the other.
• For a similar reason, Hammersmith has two codes and any data written to Hammersmith (via Bank/Monument) will appear twice in the memory dumper.
• The included module for handling the Tube map has the data to create routes across Tube lines (through interchanges), but this functionality does not yet exist.
• Breakpoints cannot be set: an MCresc script will run to completion unless paused manually.
• The debugger is currently hardcoded to load a Hello World script.
• Live editing of the source code is not currently supported.