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

[Satoshi N. <sna...@in...>]

Hi Laurent.

>    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.

I think it might be difficult.
Because the second argument accepts a string in raw encodings like 'i@:'.

--
Satoshi Nakagawa


On 2007/07/15, at 22:58, Laurent Sansonetti wrote:

> 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/