title: How can I create a macro in Objective C to execute many modules in runtime?
body: <p>In this source code is a link for module FirstDetailViewController</p>
  
  <pre><code>FirstDetailViewController *newDetailViewController = [[FirstDetailViewController alloc] initWithNibName:@"FirstDetailView" bundle:nil];
  detailViewController = newDetailViewController;
  </code></pre>
  
  <p>I want that a string </p>
  
  <pre><code>module = [[NSString] alloc] initWithString:@"SecondDetailViewController"];
  </code></pre>
  
  <p>I want to convert string module to code up for alter in runtime</p>
  
  <pre><code>module *newDetailViewController = [[module alloc] initWithNibName:module bundle:nil];
  detailViewController = newDetailViewController;
  </code></pre>
  
  <p>where module is many names</p>
  
  <pre><code>module = [[NSString] alloc] initWithString:@"ClientDetailViewController"];
  …;
  module = [[NSString] alloc] initWithString:@"FriendDetailViewController"];
  …;
  module = [[NSString] alloc] initWithString:@"FishDetailViewController"];
  …;
  </code></pre>
  
  <p>How can I use variable module to implement this?</p>