Lua with C/C++/Java/Javascript syntax
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doc Start changing the docs to describe LJS Nov 26, 2018
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src Fix parameter type Dec 12, 2018
tests Add more tests Dec 10, 2018
.gitignore First public release Nov 23, 2018
LICENSE Initial commit Nov 23, 2018
Makefile Fix make test Dec 7, 2018 typo fix Jan 9, 2019
ljs.cbp Fix make test Dec 7, 2018
table-decl.ljs Allow strings to be keys in tables without [] Dec 6, 2018
test.ljs Do not allow duplicated declarations Nov 28, 2018


Lua with C/C++/Java/Javascript syntax

Here is some code to see how it's like:

/* Limited json style table declaration */
var json = {"name": "bob"};
var A = {t: {f: 7}, n: 3}
var ary = [1,2,3,4]; //Array style declaration, syntax sugar for {}
var num = 5;

if( == "bob") print("Hello Bob !"); // if/ese like in C/C++/Java/Javascript 
else if( == "mary") print("A pretty woman !");
else print("Nice to meet you !");

for(i=1, 10) print(i);
for(k,v in pairs(json)) print(k,v);

for(k,v in pairs(A)) { // blocks are curly braces delimited
	if(k == "one") continue;
	print(k, type(k), v);

while(num > 0) --num; //pre inc/dec operators
num += 5; // compound operators
while(num > 0) {
num += 5;
do { //conventional do/while
	if(num == 3) goto update;
	//inline boolean expression
	print(num == 2 ? "it's a two" : "it's a " .. num);
} while(num > 0);

function doIt(p : string) : string { // functions and variables can have an anotation
	return "Done " .. p;


function doAgain(p) {
	if(p == null) return "I don't know what to do !"; // uses "null" instead of "nil"
	return "Done " .. p;


var Engine = {
	speed : 0

function Engine::speedTo(v : integer) { //synatx sugar for function member with "this"
	this.speed = v; // use "this" instead of "self"

Engine->speedTo(12); //syntax sugar for method call with implicity "this"

I took code and ideas from :

The default extension is ".ljs".

On folder lua2ljs there is a program to convert lua sources to ljs.

lua2ljs afile.lua > afile.ljs

This is based on Lua 5.3.5, released on 26 Jun 2018.

For installation instructions, license details, and further information about Lua, see doc/readme.html.

There is also the following port from lua to ljs:

ljsjit at

ljs-5.1 at

ZeroBraneStudio port at

raptorjit-ljs at

snabb-ljs at

premake5-ljs at

CorsixTH-0.62-ljs at

The tool lua2ljs does the convertion on almost all Lua code, except dynamic Lua code inside strings, C/C++ code, auxiliar scripts and makefiles, LJS also flag as warning/error duplicate variable declarations and a revision is needed mainly using "ljsc -p -l ljsSource.ljs > /dev/null" to only compile and emit the warnings/error to stderr, then several text scans to search and replace "nil", ".lua" and Lua code inside strings, ...

Finally run the tests if available to check that it's working properly (at least with the tests).