JScript

NOTE: This had nothing to do with Microsoft's dialect of EcmaScript

WARNING: Currently, this code is undocumented. Proceed with caution and a psychiatrist.

JScript is an engine, capable of running EcmaScript 5, written entirely in Java. This engine has been developed with the goal of being easy to integrate with your preexisting codebase, THE GOAL OF THIS ENGINE IS NOT PERFORMANCE. My crude experiments show that this engine is 50x-100x slower than V8, which, although bad, is acceptable for most simple scripting purposes. Note that although the codebase has a Main class, this isn't meant to be a standalone program, but instead a library for running JavaScript code.

Example

The following is going to execute a simple javascript statement:

var engine = new Engine();
// Initialize a standard environment, with implementations of most basic standard libraries (Object, Array, Symbol, etc.)
var env = Internals.apply(new Environment());

// Queue code to load internal libraries and start engine
var awaitable = engine.pushMsg(false, env, new Filename("tmp", "eval"), "10 + Math.sqrt(5 / 3)", null);
// Run the engine on the same thread, until the event loop runs empty
engine.run(true);

// Get our result
System.out.println(awaitable.await());