nl_tokens: 次のタスクを実行します
pl_tokens: function _iterator ( err , res ) { if ( this . _interrupt ) { return this ; } if ( ! this . _alive ) { throw new Error ( 'this bucks object already destroyed.' ) ; } //taskから渡ってきたresを配列に保持して最後に返す res ? this . _results . push ( res ) : this . _results . push ( null ) ; var task = this . _tasks . shift ( ) ; if ( ! task ) { // end of task return this . destroy ( err ) ; } try { var self = this ; // handle task task ( <mask> , res , function ( err , res ) { self . _iterator ( err , res ) ; return this ; } , this . _taskcount ++ ) ; } catch ( exception ) { if ( ! this . _results ) { // this instance already destroyed. // this exception is uncaught exception. if ( Bucks . DEBUG ) { // if DEBUG, logging logError ( exception ) ; } if ( Bucks . _isOnError ) { Bucks . _onError ( exception , this ) ; } else { throw exception ; } } // handle error this . _iterator ( exception , null ) ; } return this ; }