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

[Motohiro T. <mo...@gm...>]

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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