This is a "snippet" of a MKNetworkKit method in Objective-C and RubyMotion

loginWithUsername Obj-C version

// How to use..!
[MyNetworkClass loginWithUsername:self.username.text 
                password:self.password.text 
	        responseBlock:^(NSDictionary* jsonDict, NSError* error) {
		  if([[jsonDict objectForKey:@"result"] boolValue]){
		    // Logged in!									  	
         	  }
            	}
];

// IMPLEMENTATION

typedef void(^JSONBlock)(NSDictionary* jsonDict, NSError* error);

MKNetworkEngine* _sharedEngine;

+ (MKNetworkOperation *)loginWithUsername:(NSString *)username password:(NSString *)password responseBlock:(JSONBlock)block {
    
	// Dictionary with objectsForKeys
	NSDictionary* params = @{@"username" : username, @"password" : password};
	MKNetworkOperation* op = [_sharedEngine operationWithPath:@"login.php" params:params httpMethod:@"POST"];

	// Post login credentials in background
	[op onCompletion:^(MKNetworkOperation *completedOperation) {
		
		// Convert to JSON-data in background
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
            NSError* error;
            NSDictionary* json = [NSJSONSerialization JSONObjectWithData:completedOperation.responseData options:0 error:&error];
			
			// Call block on main thread again
            dispatch_async(dispatch_get_main_queue(), ^{
      				if(error)
      					block(nil, error);
      				else		
      					block(json, nil);
            });
        });
	} onError:^(NSError *error) {
		block(nil, error);
    }];
    [_sharedEngine enqueueOperation:op forceReload:YES];

	return op;
}

loginWithUsername RubyMotion version

# How to use..!
MyNetworkClass.loginWithUsername(self.username.text, password: self.password.text, responseBlock: 
  lambda |jsonDict, error| do
    unless jsonDict["result"].nil?
      # logged in
    end
  end 
)

# IMPLEMENTATION

def loginWithUsername(username, password: password, responseBlock: block)

  params = {"username" => username, "password" => password}
  op = _sharedEngine.operationWithPath("login.php", params: params, httpMethod: "POST")

  op.onCompletion(
    lambda |completedOperation| do 
      Dispatch::Queue.concurrent("com.company.application.tasks").async do 
          error = Pointer.new(:object)
          json = NSJSONSerialization.JSONObjectWithData(completedOperation.responseData, options: 0, error: error)

          Dispatch::Queue.main.async do
              block(json, nil) unless error
          end
      end
    end,
  onError: 
    lambda |error| do
      block(nil, error)
    end
  )
  _sharedEngine.enqueueOperation(op, forceReload: true)

  op
end

While the snippets are not that different size wise there are some minor differences. I have not compiled and tested the code, just tried to translate it as best I can.

Most people will argue that the reason to pick Ruby(RubyMotion) over Obj-C is because the amount of code you will have to write to accomplish something, I find this to be the incorrect argument to successfully understand the major difference. What I have found to be the better way of approaching this subject is the style of coding you are comfortable with and maybe even familiar with. This however was not the case in my situation, since I wasn't familiar with either one of the two. All in all, after spending the past months learning Ruby and Obj-C(Cocoa Touch in particular), I find that it feels more natural to express yourself in code using Ruby than Objective-C.

Feel free to correct my Gist if you find it to contain errors.