View source for Development:Calculated question function find all question dataset names

Description of the function find_all_question_dataset_names()
This is an adaptation of the actual code in datasetdependent/datasetdefinition.php 
  function find_all_question_dataset_names(&$question, &$mandatorydatasets, &$possibledatasets) {
    // Returns the possible dataset names found in the text and answers
    $possibledatasets = $this->find_dataset_names($question->questiontext);
    foreach ($question->options->answers as $answer) {
               $mandatorydatasets += $this
                ->find_dataset_names($answer->answer);
        }
    }
   // construct the complete list with a single entry for each dataset name
     $allpossibledatasets=array();
     foreach ($mandatorydatasets as $datasetname) {
         if (!isset($allpossibledatasets[$datasetname])) {
            $allpossibledatasets[$datasetname]=$datasetname;
         }
     }    
         foreach ($possibledatasets as $datasetname) {
            if (!isset($allpossibledatasets[$datasetname])) {
                $allpossibledatasets[$datasetname]=$datasetname;
            }
        } 
        return fullclone($allpossibledatasets);   //fullclone() necessary; array of objects
    }