[devrieda]

This is a little bit of an older article and Apple has since been working on MacRuby (http://www.macruby.org/trac/wiki/MacRuby) which is poised to replace RubyCocoa. MacRuby adds a special syntax to Ruby to better deal with the keyed arguments. From the docs:

Objective-C:

  NSWindow *window = [[NSWindow alloc] 
      initWithContentRect:frame 
      styleMask:NSBorderlessWindowMask 
      backing:NSBackingStoreBuffered 
      defer:false];

RubyCocoa:

  window = NSWindow.alloc.initWithContentRect_styleMask_backing_defer(
      frame,
      NSBorderlessWindowMask,
      NSBackingStoreBuffered,
      false)

MacRuby:

  window = NSWindow.alloc.initWithContentRect frame, 
      styleMask:NSBorderlessWindowMask,
      backing:NSBackingStoreBuffered,
      defer:false

[look_lookatme]

This is not a special syntax. It's just ruby 1.9 specific hash literal syntax.

[jimbokun]

But it looks like the important thing is that they have found a way to automatically map this syntax to Objective C method names.

EDIT: Or, as the MacRuby docs put it:

"MacRuby has a modified version of the parser which detects calls or method definitions using one regular argument, and other arguments using the key/value pair syntax. It will reconstruct the Objective-C full selector if needed. The method name that will be used in the Ruby VM is the same as the Objective-C selector."

http://www.macruby.org/trac/wiki/HowDoesMacRubyWork