wax

https://github.com/probablycorey/wax

ax is a framework that lets you write native iPhone apps in Lua. It bridges Objective-C and Lua using the Objective-C runtime. With Wax, anything you can do in Objective-C is automatically available in Lua! What are you waiting for, give it a shot!

Why write iPhone apps in Lua?

I love writing iPhone apps, but would rather write them in a dynamic language than in Objective-C. Here are some reasons why many people prefer Lua + Wax over Objective-C...

• Automatic Garbage Collection! Gone are the days of alloc, retain, and release.

• Less Code! No more header files, no more static types, array and dictionary literals! Lua enables you to get more power out of less lines of code.

• Access to every Cocoa, UITouch, Foundation, etc.. framework, if it's written in Objective-C, Wax exposes it to Lua automatically. All the frameworks you love are all available to you!

• Super easy HTTP requests. Interacting with a REST webservice has never been eaiser

• Lua has closures, also known as blocks! Anyone who has used these before knows how powerful they can be.

• Lua has a build in Regex-like pattern matching library.

Examples

For some simple Wax apps, check out the examples folder.

How would I create a UIView and color it red?

-- forget about using alloc! Memory is automatically managed by Wax
view = UIView:initWithFrame(CGRect(0, 0, 320, 100))

-- use a colon when sending a message to an Objective-C Object
-- all methods available to a UIView object can be accessed this way
view:setBackgroundColor(UIColor:redColor())

What about methods with multiple arguments?

-- Just add underscores to the method name, then write the arguments like
-- you would in a regular C function
UIApplication:sharedApplication():setStatusBarHidden_animated(true, false)

How do I send an array/string/dictionary

-- Wax automatically converts array/string/dictionary objects to NSArray,
-- NSString and NSDictionary objects (and vice-versa)
images = {"myFace.png", "yourFace.png", "theirFace.png"}
imageView = UIImageView:initWithFrame(CGRect(0, 0, 320, 460))
imageView:setAnimationImages(images)

What if I want to create a custom UIViewController?

-- Created in "MyController.lua"
--
-- Creates an Objective-C class called MyController with UIViewController
-- as the parent. This is a real Objective-C object, you could even
-- reference it from Objective-C code if you wanted to.
waxClass{"MyController", UIViewController}

function init()
  -- to call a method on super, simply use self.super
  self.super:initWithNibName_bundle("MyControllerView.xib", nil)
  return self
end

function viewDidLoad()
  -- Do all your other stuff here
end

You said HTTP calls were easy, I don't believe you...

url = "http://search.twitter.com/trends/current.json"

-- Makes an asyncronous call, the callback function is called when a
-- response is received
wax.http.request{url, callback = function(body, response)
  -- request is just a NSHTTPURLResponse
  puts(response:statusCode())

  -- Since the content-type is json, Wax automatically parses it and places
  -- it into a Lua table
  puts(body)
end}

Since Wax converts NSString, NSArray, NSDictionary and NSNumber to native Lua values, you have to force objects back to Objective-C sometimes. Here is an example.

local testString = "Hello lua!"
local bigFont = UIFont:boldSystemFontOfSize(30)
local size = toobjc(testString):sizeWithFont(bigFont)
puts(size)