main( int argc,char* argv[] )
{
  switch( argc )
    {
    case 2:
      argv[2] = NULL;
    case 3:
      exec( argv[1],argv[2] );
      break;
    default:
      cout << "Usage: run-parser demeter-input-file [start-symbol]"
	   << endl;
      break;
    }

  exit( 0 );
}