}
case YIELD: {
final LuaThread r = LuaThread.getRunning();
if ( LuaThread.isMainThread( r ) )
error("main thread can't yield");
return r.yield( args );
}
case WRAP: {
final LuaValue func = args.checkfunction(1);
final LuaThread thread = new LuaThread(func, func.getfenv());
CoroutineLib cl = new CoroutineLib();