Question

I’m getting what XCode labels an ARC Issue that I have a rather hard time to parse. I have this class:

typedef void (^sig_cb_t)(NSString *parm);

@protocol Signaleer
// <snip>
-(void) connect:(NSString *) verb
          parm:(NSString*) param
      callback:(sig_cb_t)callback;
@end

// In another header:
@interface Switchboard : NSObject <Signaleer> {
   @private
   NSMutableDictionary *bus;
}

// In init: method:
bus = [[NSMutableDictionary alloc] init];

// actual implementation:
-(void) connect: (NSString *)verb
           parm:(NSString*)parm
       callback:(sig_cb_t)callback {
  NSMutableArray *callbacks = [self.bus objectForKey:verb];
  NSArray *signal = [NSArray arrayWithObjects:callback, parm, nil];
  if (callbacks == nil) {
    NSArray *initial = [NSArray arrayWithObjects:signal, verb, nil];
    [bus setObject: initial, forKey:verb];
  } else {
    [callbacks addObject:signal];
  }
}

The line [bus setObject: initial, verb] results in the error No visible @interface for 'NSMutableDictionary' declares the selector 'setObject:'. Anyone who can explain this?

Answer 1

I assume you are referring here to the line:

[bus setObject: initial, forKey:verb];

(you write [bus setObject: initial, verb] in the last line of your question which I assume is a mistake)

Both lines have a comma in there, which shouldn’t be there.