function IteratorStep ( iterator ) {
    var result = IteratorNext(iterator);
    return IteratorComplete(result) === true ? false : result;
  }
function IteratorStep ( iterator ) {
    var result = IteratorNext(iterator);
    return IteratorComplete(result) === true ? false : result;
  }
function IteratorStep ( iterator ) { var result = IteratorNext ( iterator ) ; return IteratorComplete ( result ) === true ? false : result ; }
7.4.5 IteratorStep ( iterator )
7 . 4 . 5 IteratorStep ( iterator )