Loop-switch sequence

A loop-switch sequence is a specific derivative of the spaghetti code programming antipattern which describes the obfuscating of a clear process of steps with a byzantine switch-within-a-loop idiom.

Note: it is not an antipattern to use a switch statement within a loop. It is only an antipattern to do so to model a sequence of events. The most common example of a correct use of a switch within a loop is an event handler. (see Event-Driven Programming, Event Loop, and Event-driven finite state machine).

Example of antipattern (pseudocode)

  // parse a key, a value, then three parameters 

  String key;
  String value;
  List<String> args;
  
  for ( int i = 0; i < 5; ++i )
  {
    switch( i )
    {
      case 0 :
        key = stream.parse();
        break;
  
      case 1 :
        value = stream.parse();
        break;
  
      default:
        args.add( stream.parse() );
    }
  }

Refactored solution (pseudocode)

  // parse a key and value
  
  String key = stream.parse();
  String value = stream.parse();
  
  // parse 3 parameters

  List<String> args;
  
  for ( int i = 0; i < 3; ++i )
  {
    args.add( stream.parse() );
  }