Re: [Rubycocoa-talk] return simple int from Ruby to ObjC

[Laurent S. <lsa...@ap...>]

Oops, please try

   objc_method :getInt, ['int']

The second argument of objc_method is supposed to be an Array. I will  
fix the method to accept a String.

Laurent

On Jul 15, 2007, at 3:55 PM, Motohiro Takayama wrote:

> Laurent:
>
> Thanks for your quick reply.
>
> I tried your advice, and observed strange behavior.
>
> class Hoge < OSX::NSObject
> 	objc_method :getInt, 'int'
> 	def getInt
> 		5
> 	end
> end
>
> and when call this, NSLog shows:
>
> 2007-07-15 22:50:15.667 retval[7097] XXX returning ffi type void for
> unrecognized encoding 'nt'
>
> I'm wondering why "i" of int is lack...
>
> 2007/7/15, Laurent Sansonetti <lsa...@ap...>:
>> When creating a Ruby method like this, without providing its ObjC
>> runtime signature, RubyCocoa will assume that all arguments and the
>> return value are Objective-C objects (of the type 'id'). Because  
>> there
>> is no way for RubyCocoa to know. This is why you get from the ObjC
>> world an NSNumber and not an "int".
>>
>> To work around this, you need to register the Ruby method into the
>> ObjC runtime:
>>
>>   def getInt ... end
>>   objc_method :getInt, 'int'
>>
>> This will register getInt as a method that doesn't take any argument
>> and returns a C integer.
>>
>> Usually when you are overriding an ObjC method from Ruby, or
>> implementing an ObjC informal protocol in Ruby, you don't need to use
>> objc_method. But in this special case, it is required. Fortunately,
>> most people won't need to use it.
>>
>> Laurent
>>
>> On Jul 15, 2007, at 3:01 PM, Motohiro Takayama wrote:
>>
>>> Hi,
>>>
>>> I'm wondering how to return simple "int" type value from Ruby code  
>>> to
>>> Objective-C code.
>>> Ruby code passes Fixnum, and Objective-C code recieves NSCFNumber
>>> instead of simple int.
>>> Any suggestion ?
>>>
>>>
>>> Ruby code:
>>>
>>> class Hoge < OSX::NSObject
>>>   def getInt
>>>     5
>>>   end
>>> end
>>>
>>>
>>> Objective-C code:
>>>
>>>      Class helper = NSClassFromString(@"Hoge");
>>>      id hoge = [[helper alloc] init];
>>>      NSLog(@"%@ %d", [[hoge getInt] class], [(NSNumber *)[hoge  
>>> getInt]
>>> decimalValue]);
>>>
>>>
>>> and those show:
>>>
>>> 2007-07-15 21:52:56.954 retval[5100] NSCFNumber 8448
>>>
>>>
>>> thanks,
>>>
>>> --
>>> Motohiro Takayama
>>> http://blog.deadbeaf.org/
>>>
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