Sam Soffes

RubyMotion Review

Posted on

RubyMotion was released today. RubyMotion lets you write iPhone and iPad apps in Ruby.

RubyMotion is a revolutionary toolchain for iOS. It lets you quickly develop and test native iOS applications for iPhone or iPad, all using the awesome Ruby language you know and love.


It's a very exciting new product from Laurent Sansonetti, the creator of MacRuby. He was at Apple working on MacRuby full-time, but decided to leave and do his own thing. This is what he made.

Initial Reaction

After paying the $149.99 for RubyMotion, I was excited to try it out. The installation process was super easy. There was a small issue with it not finding my version of Xcode right away, but I have a pre-release version, so that's understandable.

I got my first app up and running in less than a minute (once I got my Xcode issues sorted out). Already way impressed.

Ruby Instead of Objective-C

Writing Ruby code like this is amazing.

@window = UIWindow.alloc.initWithFrame(UIScreen.mainScreen.bounds)

Here's the same code in Objective-C

self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
[self.window makeKeyAndVisible];

Here's another example. Ruby code:

navigationBar = UINavigationBar.appearance
navigationBar.setBackgroundImage(UIImage.imageNamed('nav-background.png'), forBarMetrics: UIBarMetricsDefault)
  UITextAttributeFont: UIFont.cheddarFontWithSize(24.0),
  UITextAttributeTextShadowColor: UIColor.colorWithWhite(0.0, alpha:0.4),
  UITextAttributeTextColor: UIColor.whiteColor


id navigationBar = [UINavigationBar appearance];
[navigationBar setBackgroundImage:[UIImage imageNamed:@"nav-background.png"] forBarMetrics:UIBarMetricsDefault];
[navigationBar setTitleTextAttributes:[[NSDictionary alloc] initWithObjectsAndKeys:
  [UIFont cheddarFontWithSize:24.0f], UITextAttributeFont,
  [UIColor colorWithWhite:0.0f alpha:0.4f], UITextAttributeTextShadowColor,
  [UIColor whiteColor], UITextAttributeTextColor,

I'm totally in love with the Ruby syntax over Objective-C. Also, I'm really looking forward to using mixins. Categories are also awesome. Want to add a method to a class? Just open the class and add it:

class UIColor
  def self.cheddarTextColor
    self.colorWithWhite(0.267, alpha:1.0)

Build Settings

The way the build system works in RubyMotion might be my favorite thing. It's just a rake task, and it's amazing.

I have custom fonts in the application I was working on. I figured this would be annoying to figure out how it wants me to tell it that I'm using a custom font. After reading the RubyMotion docs, I ran rake config to see the current configuration. It already had the correct configuration! RubyMotion detected that I added a font file to my resources folder and added the appropriate configuration for me. Amazing.

Here's an excerpt of my Rakefile:

Motion::Project::App.setup do |app| = 'Cheddar'
  app.interface_orientations = [:portrait]
  app.prerendered_icon = true
  app.icons = %w{Icon-29.png Icon-50.png Icon-57.png Icon-58.png Icon-72.png Icon-100.png Icon-114.png Icon-144.png}

I totally love this. This is a million times better than fighting with Xcode's clunky UI for configuring all of these options. I also really like that RubyMotion gives you access to edit whatever Info.plist or build settings you want.

You can just run rake config to see the entire configuration of your application. For anything you want to change, you just add the option in the Rakefile. Such a great way to do it.


The REPL (read-eval-print loop) is hands down the most amazing part of RubyMotion. It's even more advanced than Apple's tools here. Watch the demo to understand how awesome it is.

You can command-click a view on the screen and then it becomes self in the console. Say you command-click a UILabel in the simulator. You can type the following command:

>> self.text = 'Awesome'

and see label's text updates immediately.

I was trying to see if some fonts were being loaded in my RubyMotion application. Normally, I would add some logs to the beginning of my application delegate to see what's going on. I realized I had a console, so just typed what I was going to log in the console. There was the output immediately. Amazing.


I'm also really looking forward to testing with Ruby tools. The Objective-C community rarely tests stuff. The Ruby community is all about it. My theory is that's due to the compiled nature of Objective-C. Anyway, I'm really excited to use MiniTest to test my apps. The RubyMotion documentation is a bit lacking here at the moment.

Final Thoughts

I am quite confident that if Laurent had stayed at Apple, we wouldn't have anything close to this today for two reasons. Apple is heavily invested in Objective-C. Objective-C is fantastic. Apple has been using it for years and years. It's not "broken" per se. Secondly, I think the main reason is this is a lot of new stuff. Apple is a giant company. Stuff like this would take a ton of effort navigating internal politics to pull off. I'm glad he left and made it a reality.

I really like the build system, configuration, and writing Ruby.

I plan on converting Cheddar to RubyMotion in my free time. I doubt I'll ship a RubyMotion version anytime soon, but I'm not opposed to the idea. Overall, RubyMotion is great. It means more people on the iOS platform, which is a good thing.