nl_tokens: Provides the most common I / O operations .
pl_tokens: function DataHandler ( options ) { options = options || { } ; var dataHandler = options . db . _db . _driver || 'disk' ; switch ( dataHandler ) { // load the driver to be used just once case 'memory' : this . dataHandlerDriver = new Memory ( options ) ; break ; case 'disk' : default : this . dataHandlerDriver = new Disk ( <mask> ) ; } }