Gamesys

Lua on the Web

• Lua.js
• Ljs
• lua.vm.js
• Moonshine

Lua.js

Lua.js

• Translates Lua code to JavaScript.
• Preprocess your Lua.
• Includes reimplemented standard library.
• 19k (5k gzipped) + translated code.
• Also runs in ActionScript (Flash).

Lua.js

Before:

After:

Lua.js

Result:

Löve

Löve

Löve WebPlayer:

https://github.com/ghoulsblade/love-webplayer

Lua.js

Support:

• Firefox 4+
• Chrome 14+ *
• Safari 4+ *
• IE 9+
• iOS 3+ *
• Android 2.2+ *

* Unable to test earlier versions

Lua.js

• A lot of Lua is not implemented, including:
  • Coroutines.
  • Pattern matching functions (gsub, find, match).
  • require()
  • xpcall()

Lua.js

• Not consistant:
  • Incorrect coercions
  • unpack()
  • string.format()
  • Length operator (#)

Lua.js

• Debugging
  • Error message and stack traces are internal
  • No source mapping
• Pain to inject variables in the Lua environment.

Lua.vm.js

Lua.vm.js

• C Lua compiled to JavaScript using Emscripten.
• Lua 5.2
• Runs Lua code directly.
• It just works.
• 644k (199k gzipped).

Lua.vm.js

Support:

• Firefox 4+
• Chrome 17+
• Safari 6+
• IE 10+
• iOS 6+
• Android 4.1+

Lua.vm.js

• Relatively heavy
• Slow on low-power devices.
• Slow(ish) starting up.
• No big projects using it yet
• Debugging

Lua.vm.js

• Host API
  • js.global.document
  • js.new.WebSocket()
• Can't pass tables out into host environment.
• Issues calling host functions

Moonshine

Moonshine

• Runs Lua bytecode.
• Reimplements the Lua bytecode instruction set
• Includes reimplemented standard library.
• 60k (19k gzipped).
• Also runs in ActionScript (Flash).

Moonshine

• Coroutines.
• Pattern matching.
• require()
• Packaged with debug engine.

Jackpotjoy

Jackpotjoy

Games in Lua:

Moonshine

Support:

• Firefox 3+ *
• Chrome 14+ *
• Safari 4+ *
• IE 6+ *
• iOS 3+ *
• Android 2.2+ *

* Unable to test earlier versions

Moonshine

• Balanced matching: %b
• Some standard library functions missing:
  • debug
  • io
  • Parts of os

Moonshine

Future:

• JIT?
• Implement Lua 5.2.
• Integrate into Löve WebPlayer.
• Integrate with remotedebug.org
• Virtual file system using local storage?