Object-C / iPhone and Switch Statements

Lately (meaning the last year or so) I started to be a lousy blogger. Either I have nothing to say or I am so busy that I don’t have time for it. So this time where I started to develop and iPhone app for hire with a hard deadline leaving a lot of work to be done. So far the project progresses well and there is little head banging. Still I ran into an old strange issue with Object-C and wasted a few hours. Eventually I dawned on my that I had this issue beforehand and then it was fixed right away.

So what happened? I wanted to create an enum to store a flag of what the program should do next like display the row, display the row’s detail or query the server for data. That looked like this:

enum Actions {
    row,
    detail,
    search
};
typedef enum Actions Actions;

Then I wanted to use it in a switch-case statement to execute the appropriate action:

switch( actions ) {
    case search:
        NSString *query = (NSString *) action.data;
        return;
    case detail:
        childViewController = [[TestViewController alloc]
              initWithNibName:@"TestDetail"
                                bundle:nil];
        break;
    default:
        NSDictionary *venue = (NSDictionary *) action.data;
        childViewController = [[Test2TableViewController alloc]
                                      initWithRows:rows];
}

But then I get this error: Expected expression before NSString which looks wrong. I am not sure why but the fix is simple. One just needs to wrap each block between case ???: and break into a {} block. That’s it:

switch( actions ) {
    case search:
        {
            NSString *query = (NSString *) action.data;
            return;
        }
    case detail:
        {
            childViewController = [[TestViewController alloc]
                  initWithNibName:@"TestDetail"
                                   bundle:nil];
        }
        break;
    default:
        {
            NSDictionary *venue = (NSDictionary *) action.data;
            childViewController = [[Test2TableViewController alloc]
                                      initWithRows:rows];
        }
}

Hope that helps - Andy