Re: [Rubycocoa-talk] Ruby-fying the SyncServices - SimpleStickies tutorial fom Apple

[Jonathan P. <jp...@dc...>]

On 18 Nov 2005, at 23:00, Rupert BARROW wrote:

> - I cannot programmatically (from Ruby) add objects to the Notes  
> controller to get them inserted into GUI

I can't see any code that tries to do that. Can you indicate what  
you've tried?

I've figured out the problem with the key-value coding. You can make  
the following simplifications to the code:

  (1) no need for 'kvc_wrapper'
  (2) no need to call kvc_wrapper_representation at all
  (3) no need for @_changed instance variable or corresponding methods

Important bit - change this:

> 	def valueForUndefinedKey(k)
> 		@_representation.valueForKey(k)
> 	end
> 	
> 	def setValue_ForUndefinedKey(v, k)
> 		@_representation.setValueForKey(v, k)
> 	end

to this:

   def rbValueForKey(k)
     @_representation.valueForKey(k)
   end

   def rbSetValue_forKey(v,k)
     self.willChangeValueForKey(k)
     @_representation.setValueForKey(v,k)
     self.didChangeValueForKey(k)
   end

Here's why:

RubyCocoa (in OverrideMixin.m) overrides valueForUndefinedKey: and  
setValue:forUndefinedKey: and passes them through to rbValueForKey  
and rbSetValue_forKey, which are defined in oc_import.rb.

The definition in oc_import.rb looks for ruby-like setters/getters  
and calls them, calling the willChange/didChange... methods when  
necessary also.

So, for example, [obj setValue: x forUndefinedKey: @"y"] ends up  
calling 'obj.y = x' in ruby-land.

Since the valueForUndefinedKey: and setValue... methods are defined  
at a low level in OverrideMixin.m, the original definition in Note.rb  
never took effect. By overriding instead the ruby delegates  
(rbValue.. etc) we can achieve the desired effect.



I think it may be neater in the long-run to make the kvc_accessor  
methods in oc_import.rb define real methods (using  
addRubyMethod_withType) and avoid the undefined key hack altogether.  
I'll have a look into this.

Hope that makes some sense,
Jonathan