sophiebits / lljs

LLJS: Low-Level JavaScript

LLJS

LLJS is a typed dialect of JavaScript that offers a C-like type system with manual memory management. It compiles to JavaScript and lets you write memory-efficient and GC pause-free code less painfully, in short, LLJS is the bastard child of JavaScript and C. LLJS is early research prototype work, so don't expect anything rock solid just yet. The research goal here is to explore low-level statically typed features in a high-level dynamically typed language. Think of it as inline assembly in C, or the unsafe keyword in C#. It's not pretty, but it gets the job done.

Try It Online

Usage

For users of node.js, bin/ljc is provided.

For users of SpiderMonkey js shell, the compiler can be invoked with:

$ js ljc.js

in the src/ directory.

Memcheck

If you would like to compile with support for memory checking (detects leaks, accesses of unallocated and undefined memory locations, and double frees) then compile with the -m flag:

$ bin/ljc -m -o myscript.js myscript.ljs

And add the following code to the end of your program run to report any memory errors:

let m = require('memory');
// for SpiderMonkey do
// let m = load('memory.js')
console.log(m.memcheck.report());

The memory checker uses Proxies so if you use node.js you need to enable it with:

$ node --harmony-proxies myscript.js

Testing

To run the tests install the Mocha module then run:

export NODE_PATH=src/
mocha --compilers ljs:ljc

from the root LLJS directory.