gistfile1.rb

class AppDelegate
  def application(application, didFinishLaunchingWithOptions:launchOptions)
    window = UIWindow.alloc.initWithFrame(UIScreen.mainScreen.bounds)
    @view = UIButton.alloc.initWithFrame([[0,0],[150,150]])
    @view.backgroundColor = UIColor.redColor
    window.addSubview(@view)
    @count = 0

    window.makeKeyAndVisible
    @view.addTarget(self, action:"tapped", forControlEvents:UIControlEventTouchUpInside)

    temp_fields[:foo] = "foo"

    true
  end

  def temp_fields
    @fields ||= {}
  end

  def tapped
    foo = temp_fields[:foo]
    temp_fields[:foo] = nil # comment out this line to stop crash
    puts foo
    temp_fields[:foo] = "foo"
  end
end