Lua to Javascript translator

by Bambo • 14 years ago

46 27 14 years ago

What abilities does it have to interact with the DOM?

jballanc3• 14 years ago

Lua is a better language than Javascript in every possible way. I have half-a-mind to hack LuaJIT into Webkit, but I'm afraid that it may be futile at this point. The biggest shame in all of web development is the "type" attribute on the HTML "script" tag...

mistercow• 14 years ago

I disagree that Lua is better in every possible way. There are at least a couple of ways in which it is merely equal, yet where improvement would be possible.

jballanc3• 14 years ago

Point taken... "equal or better" in every possible way. :-)

TazeTSchnitzel• 14 years ago

Please hack LuaJIT into WebKit. I was thinking of doing something even more crazy: hack Mono into WebKit!

gruseom2• 14 years ago

I have half-a-mind to hack LuaJIT into Webkit

I've been thinking for a while that Lua and especially LuaJIT are so good that there might exist a strategy to do an end run around vendors and get LuaJIT into browsers as (initially) a plug-in. It's possible that there's a killer app waiting to be written that could run well in LuaJIT (but not JS) and that this could drive installation of such a plug-in.

azakai3• 14 years ago

> I've been thinking for a while that Lua and especially LuaJIT are so good that there might exist a strategy to do an end run around vendors and get LuaJIT into browsers as (initially) a plug-in. It's possible that there's a killer app waiting to be written that could run well in LuaJIT (but not JS) and that this could drive installation of such a plug-in.

Please don't create yet another plugin. Plugins are bad for the web, they fragment it and if they end up de-facto standards that causes many problems too.

> It's possible that there's a killer app waiting to be written that could run well in LuaJIT (but not JS) and that this could drive installation of such a plug-in.

If you think there is something that needs improving in the web platform, contributing to that would be the best thing. If you have such a killer app that does not run well enough in current JS engines, you can contribute to one of the three open source JS engines to make it able to run your killer app.

est• 14 years ago

> Lua is a better language than Javascript in every possible way.

How about unicode and regexp support?

jballanc3• 14 years ago

So regexp is easy: the Lua authors assert that their irregular-regular expressions (match library) cover the 80% use case for regular expressions while maintaining excellent performance and avoiding the hell that regexps can all too easily descend into. Based on some of the regexps that I've come across in my time...I'm inclined to agree with their decision.

As for unicode, I also rather like their approach: we give you the low level tools, and you are free to implement whatever sort of encoding support you like on top of that. I used Ruby 1.8 when a string was just a bucket-o-bytes, and now I use Ruby 1.9 where every string MUST HAVE AN ENCODING OR ELSE! Based on my experience with both, I'd much rather not have encoding forced on me. That said, it would be nice to see a unicode implementation "blessed" by the core team (but the seem loath to "bless" any libraries).

fshen• 14 years ago

Javascript is an usable language, just need an open mind to learn it.

Javascript is a simple language. Compile(translate) other language seems good. But complicated things.

ufo2• 14 years ago

Lua is simpler though

leafo• 14 years ago

This is a cool project, but sadly it's not a complete Lua. It's missing two of Lua's most powerful features:

A lot of the metatable functionality just won't work: http://www.lua.org/manual/5.1/manual.html#2.8

Second, it's missing co-routines. Which is a way to suspend the execution of a piece of code.

These features aren't possible in a compiler that simply translates from Lua to JS because JS doesn't have the ability to reproduce these concepts in its own constructs. You would have to output significantly different code to simulate these features.

Without these you're just writing JavaScript in another dialect.

bsg754• 14 years ago

Given this, what could be a legimate goal of this project?

There are more than a few language X -> Y translators (not compilers), and I suspect they all miss some aspects of the source or target language.

ufo2• 14 years ago

Looks like the only metatable stuff they don't dupport is weak references and garbage collection hooks (finalizers/destructors) Other then that t looks like the support most of the other stuff since table access and things like tha through intermediate functions such as lua_tableget and so on.

RageKit3• 14 years ago

Hum, i think everyone love javascript, but no one wants to actually write some ...

RageKit3• 14 years ago

(thats what i can deduct from all these lib to convert whatever into js)

freehunter• 14 years ago

Javascript has the benefit of being able to easily run natively on the web. Lua is more complex to get running in a browser, as other languages are as well.

Javascript has the disadvantage in that some people know and love and feel more comfortable in other languages. If you can convert from a language you love to a language that makes it easy to get into a browser... that's the dream.

snprbob86• 14 years ago

Very cool project!

I know that this is somewhat off topic, but I'm thinking about this from the perspective of the ClojureScript compiler. The translation snippets in the Lua.js README make me really thankful for the design of Clojure. It's highly amenable to compilation. As a result ClojureScript is able to produce extremely well optimized output. For simple cases, the translation is no more unreadable than CoffeeScript. But even for complex cases, the performance is excellent because most forms compile to relatively plain & boring javascript.

    Lua      init(1, 2, 3)
    Lua.js   lua_call(lua_tableget(lua_script, "init"), [1, 2, 3]);
    CLJ      (init 1 2 3)
    CLJS     cljs.user.init.call(null, 1, 2, 3)

    Note that cljs.user is the default namespace in the ClojureScript REPL.

    Lua      local numActive = activeChars.count
    Lua.js   var numActive = lua_tableget(lua_tableget(lua_script, "activeChars"), "count")[0];
    CLJ      (let [num-active (.-count active-chars)])
    CLJS     var num_active__10317 = cljs.user.active_chars.count;

    Lua      local distFromCenter = get_distance({x=1, y=2})
    Lua.js   var distFromCenter = lua_call(lua_tableget(lua_script, "get_distance"), [lua_newtable(null, "x", 1, "y", 2)])[0];
    CLJ      (let [distance-from-center (get-distance {:x 1 :y 2})])
    CLJS     var distance_from_center__10322 = cljs.user.get_distance.call(null, cljs.core.ObjMap.fromObject(["\ufdd0'x", "\ufdd0'y"], {"\ufdd0'x":1, "\ufdd0'y":2}));

    Lua.js wins on that last example, but if you need more speed, you can get it. All of the JavaScript primitives are exposed with highly performant macros:

    CLJ      (aget (js-obj "x" 1 "y" 2) "x")
    CLJS     ({"x":1, "y":2}["x"])

haberman2• 14 years ago

Very cool! Ignoring the relative strengths/weaknesses of the languages themselves, JavaScript's killer feature is that it is ubiquitous in web browsers and Lua's killer feature is that it has an extremely small and easy-to-embed implementation. With a project like this you could write code in Lua and get the best of both worlds.

When it comes to actually comparing the languages though, Lua is the language that you'd get if you had 10 years to refine JavaScript's design and throw out the cruft, IMO.

bsg754• 14 years ago

Don't you lose the compact advantage of Lua in the conversion?

haberman2• 14 years ago

Sure, but it could allow a single code-base to be portable to both to the tiny Lua VM and the web.

Lua to Javascript translator

Related Stories