From fbe2cfead160048fcece57333a07633aa47d9d34 Mon Sep 17 00:00:00 2001 From: pichetp Date: Tue, 16 Sep 2008 12:59:00 +0000 Subject: [PATCH] MDL-16505 Removing qtype_datasetdependent questiontype --- .../datasetdefinitions_form.php | 2 +- .../datasetitems_form.php | 2 +- question/type/calculated/questiontype.php | 617 +++++++++++++++++- 3 files changed, 602 insertions(+), 19 deletions(-) rename question/type/{datasetdependent => calculated}/datasetdefinitions_form.php (98%) rename question/type/{datasetdependent => calculated}/datasetitems_form.php (99%) diff --git a/question/type/datasetdependent/datasetdefinitions_form.php b/question/type/calculated/datasetdefinitions_form.php similarity index 98% rename from question/type/datasetdependent/datasetdefinitions_form.php rename to question/type/calculated/datasetdefinitions_form.php index 26935acc67..bd7b6bffce 100644 --- a/question/type/datasetdependent/datasetdefinitions_form.php +++ b/question/type/calculated/datasetdefinitions_form.php @@ -41,7 +41,7 @@ class question_dataset_dependent_definitions_form extends moodleform { $mandatorydatasets += $this->qtypeobj->find_dataset_names($answer->answer); } }else{ - foreach ($SESSION->datasetdependent->questionform->answers as $answer){ + foreach ($SESSION->calculated->questionform->answers as $answer){ $mandatorydatasets += $this->qtypeobj->find_dataset_names($answer); } } diff --git a/question/type/datasetdependent/datasetitems_form.php b/question/type/calculated/datasetitems_form.php similarity index 99% rename from question/type/datasetdependent/datasetitems_form.php rename to question/type/calculated/datasetitems_form.php index 1fba187f7b..435fd03224 100644 --- a/question/type/datasetdependent/datasetitems_form.php +++ b/question/type/calculated/datasetitems_form.php @@ -34,7 +34,7 @@ class question_dataset_dependent_items_form extends moodleform { $this->qtypeobj =& $QTYPES[$this->question->qtype]; //get the dataset defintions for this question if (empty($question->id)) { - $this->datasetdefs = $this->qtypeobj->get_dataset_definitions($question->id, $SESSION->datasetdependent->definitionform->dataset); + $this->datasetdefs = $this->qtypeobj->get_dataset_definitions($question->id, $SESSION->calculated->definitionform->dataset); } else { if (empty($question->options)) { $this->get_question_options($question); diff --git a/question/type/calculated/questiontype.php b/question/type/calculated/questiontype.php index b71606231a..34b781539e 100644 --- a/question/type/calculated/questiontype.php +++ b/question/type/calculated/questiontype.php @@ -6,13 +6,16 @@ /// QUESTION TYPE CLASS ////////////////// -require_once("$CFG->dirroot/question/type/datasetdependent/abstractqtype.php"); +define("LITERAL", "1"); +define("FILE", "2"); +define("LINK", "3"); -class question_calculated_qtype extends question_dataset_dependent_questiontype { +class question_calculated_qtype extends default_questiontype { // Used by the function custom_generator_tools: var $calcgenerateidhasbeenadded = false; + public $virtualqtype = false; function name() { return 'calculated'; @@ -285,6 +288,57 @@ class question_calculated_qtype extends question_dataset_dependent_questiontype } } + function restore_session_and_responses(&$question, &$state) { + if (!ereg('^dataset([0-9]+)[^-]*-(.*)$', + $state->responses[''], $regs)) { + notify ("Wrongly formatted raw response answer " . + "{$state->responses['']}! Could not restore session for " . + " question #{$question->id}."); + $state->options->datasetitem = 1; + $state->options->dataset = array(); + $state->responses = array('' => ''); + return false; + } + + // Restore the chosen dataset + $state->options->datasetitem = $regs[1]; + $state->options->dataset = + $this->pick_question_dataset($question,$state->options->datasetitem); + $state->responses = array('' => $regs[2]); + return true; + } + + function create_session_and_responses(&$question, &$state, $cmoptions, $attempt) { + // Find out how many datasets are available + global $CFG, $DB; + if(!$maxnumber = (int)$DB->get_field_sql( + "SELECT MIN(a.itemcount) + FROM {question_dataset_definitions} a, + {question_datasets} b + WHERE b.question = ? + AND a.id = b.datasetdefinition", array($question->id))) { + print_error('cannotgetdsforquestion', 'question', '', $question->id); + } + + // Choose a random dataset + $state->options->datasetitem = rand(1, $maxnumber); + $state->options->dataset = + $this->pick_question_dataset($question,$state->options->datasetitem); + $state->responses = array('' => ''); + return true; + } + + function save_session_and_responses(&$question, &$state) { + global $DB; + $responses = 'dataset'.$state->options->datasetitem.'-'. + $state->responses['']; + // Set the legacy answer field + if (!$DB->set_field('question_states', 'answer', $responses, array('id'=> $state->id))) { + return false; + } + return true; + } + function create_runtime_question($question, $form) { $question = parent::create_runtime_question($question, $form); $question->options->answers = array(); @@ -345,7 +399,216 @@ class question_calculated_qtype extends question_dataset_dependent_questiontype } return true; } + function finished_edit_wizard(&$form) { + return isset($form->backtoquiz); + } + // This gets called by editquestion.php after the standard question is saved + function print_next_wizard_page(&$question, &$form, $course) { + global $CFG, $USER, $SESSION, $COURSE; + + // Catch invalid navigation & reloads + if (empty($question->id) && empty($SESSION->calculated)) { + redirect('edit.php?courseid='.$COURSE->id, 'The page you are loading has expired.', 3); + } + + // See where we're coming from + switch($form->wizardpage) { + case 'question': + require("$CFG->dirroot/question/type/calculated/datasetdefinitions.php"); + break; + case 'datasetdefinitions': + case 'datasetitems': + require("$CFG->dirroot/question/type/calculated/datasetitems.php"); + break; + default: + print_error('invalidwizardpage', 'question'); + break; + } + } + + // This gets called by question2.php after the standard question is saved + function &next_wizard_form($submiturl, $question, $wizardnow){ + global $CFG, $SESSION, $COURSE; + + // Catch invalid navigation & reloads + if (empty($question->id) && empty($SESSION->calculated)) { + redirect('edit.php?courseid='.$COURSE->id, 'The page you are loading has expired. Cannot get next wizard form.', 3); + } + if (empty($question->id)){ + $question =& $SESSION->calculated->questionform; + } + + // See where we're coming from + switch($wizardnow) { + case 'datasetdefinitions': + require("$CFG->dirroot/question/type/calculated/datasetdefinitions_form.php"); + $mform =& new question_dataset_dependent_definitions_form("$submiturl?wizardnow=datasetdefinitions", $question); + break; + case 'datasetitems': + require("$CFG->dirroot/question/type/calculated/datasetitems_form.php"); + $regenerate = optional_param('forceregeneration', 0, PARAM_BOOL); + $mform =& new question_dataset_dependent_items_form("$submiturl?wizardnow=datasetitems", $question, $regenerate); + break; + default: + print_error('invalidwizardpage', 'question'); + break; + } + + return $mform; + } + + /** + * This method should be overriden if you want to include a special heading or some other + * html on a question editing page besides the question editing form. + * + * @param question_edit_form $mform a child of question_edit_form + * @param object $question + * @param string $wizardnow is '' for first page. + */ + function display_question_editing_page(&$mform, $question, $wizardnow){ + switch ($wizardnow){ + case '': + //on first page default display is fine + parent::display_question_editing_page($mform, $question, $wizardnow); + return; + break; + case 'datasetdefinitions': + print_heading_with_help(get_string("choosedatasetproperties", "quiz"), "questiondatasets", "quiz"); + break; + case 'datasetitems': + print_heading_with_help(get_string("editdatasets", "quiz"), 'questiondatasets', "quiz"); + break; + } + + + $mform->display(); + + } + + /** + * This method prepare the $datasets in a format similar to dadatesetdefinitions_form.php + * so that they can be saved + * using the function save_dataset_definitions($form) + * when creating a new calculated question or + * whenediting an already existing calculated question + * or by function save_as_new_dataset_definitions($form, $initialid) + * when saving as new an already existing calculated question + * + * @param object $form + * @param int $questionfromid default = '0' + */ + function preparedatasets(&$form , $questionfromid='0'){ + // the dataset names present in the edit_question_form and edit_calculated_form are retrieved + $possibledatasets = $this->find_dataset_names($form->questiontext); + $mandatorydatasets = array(); + foreach ($form->answers as $answer) { + $mandatorydatasets += $this->find_dataset_names($answer); + } + // if there are identical datasetdefs already saved in the original question. + // either when editing a question or saving as new + // they are retrieved using $questionfromid + if ($questionfromid!='0'){ + $form->id = $questionfromid ; + } + $datasets = array(); + $key = 0 ; + // always prepare the mandatorydatasets present in the answers + // the $options are not used here + foreach ($mandatorydatasets as $datasetname) { + if (!isset($datasets[$datasetname])) { + list($options, $selected) = + $this->dataset_options($form, $datasetname); + $datasets[$datasetname]=''; + $form->dataset[$key]=$selected ; + $key++; + } + } + // do not prepare possibledatasets when creating a question + // they will defined and stored with datasetdefinitions_form.php + // the $options are not used here + if ($questionfromid!='0'){ + + foreach ($possibledatasets as $datasetname) { + if (!isset($datasets[$datasetname])) { + list($options, $selected) = + $this->dataset_options($form, $datasetname,false); + $datasets[$datasetname]=''; + $form->dataset[$key]=$selected ; + $key++; + } + } + } + return $datasets ; + } + /** + * this version save the available data at the different steps of the question editing process + * without using global $SESSION as storage between steps + * at the first step $wizardnow = 'question' + * when creating a new question + * when modifying a question + * when copying as a new question + * the general parameters and answers are saved using parent::save_question + * then the datasets are prepared and saved + * at the second step $wizardnow = 'datasetdefinitions' + * the datadefs final type are defined as private, category or not a datadef + * at the third step $wizardnow = 'datasetitems' + * the datadefs parameters and the data items are created or defined + * + * @param object question + * @param object $form + * @param int $course + * @param PARAM_ALPHA $wizardnow should be added as we are coming from question2.php + */ + function save_question($question, $form, $course) { + $wizardnow = optional_param('wizardnow', '', PARAM_ALPHA); + $id = optional_param('id', 0, PARAM_INT); // question id + // in case 'question' + // for a new question $form->id is empty + // when saving as new question + // $question->id = 0, $form is $data from question2.php + // and $data->makecopy is defined as $data->id is the initial question id + // edit case. If it is a new question we don't necessarily need to + // return a valid question object + + // See where we're coming from + switch($wizardnow) { + case '' : + case 'question': // coming from the first page, creating the second + if (empty($form->id)) { // for a new question $form->id is empty + $question = parent::save_question($question, $form, $course); + //prepare the datasets using default $questionfromid + $this->preparedatasets($form); + $form->id = $question->id; + $this->save_dataset_definitions($form); + } else if (!empty($form->makecopy)){ + $questionfromid = $form->id ; + $question = parent::save_question($question, $form, $course); + //prepare the datasets + $this->preparedatasets($form,$questionfromid); + $form->id = $question->id; + $this->save_as_new_dataset_definitions($form,$questionfromid ); + } else {// editing a question + $question = parent::save_question($question, $form, $course); + //prepare the datasets + $this->preparedatasets($form,$question->id); + $form->id = $question->id; + $this->save_dataset_definitions($form); + } + break; + case 'datasetdefinitions': + + $this->save_dataset_definitions($form); + break; + case 'datasetitems': + $this->save_dataset_items($question, $form); + break; + default: + print_error('invalidwizardpage', 'question'); + break; + } + return $question; + } /** * Deletes question from the question-type specific tables * @@ -379,10 +642,10 @@ class question_calculated_qtype extends question_dataset_dependent_questiontype $numericalquestion = fullclone($question); foreach ($numericalquestion->options->answers as $key => $answer) { $answer = fullclone($numericalquestion->options->answers[$key]); - $numericalquestion->options->answers[$key]->answer = $this->substitute_variables($answer->answer, + $numericalquestion->options->answers[$key]->answer = $this->substitute_variables_and_eval($answer->answer, $state->options->dataset); } - $numericalquestion->questiontext = parent::substitute_variables( + $numericalquestion->questiontext = $this->substitute_variables( $numericalquestion->questiontext, $state->options->dataset); //evaluate the equations i.e {=5+4) $qtext = ""; @@ -411,7 +674,7 @@ class question_calculated_qtype extends question_dataset_dependent_questiontype $numericalquestion = fullclone($question); foreach ($numericalquestion->options->answers as $key => $answer) { $answer = $numericalquestion->options->answers[$key]->answer; // for PHP 4.x - $numericalquestion->options->answers[$key]->answer = $this->substitute_variables($answer, + $numericalquestion->options->answers[$key]->answer = $this->substitute_variables_and_eval($answer, $state->options->dataset); } $virtualqtype = $this->get_virtual_qtype(); @@ -434,7 +697,7 @@ class question_calculated_qtype extends question_dataset_dependent_questiontype } foreach ($numericalquestion->options->answers as $key => $answer) { $answer = &$numericalquestion->options->answers[$key]; // for PHP 4.x - $answer->answer = $this->substitute_variables($answer->answer, + $answer->answer = $this->substitute_variables_and_eval($answer->answer, $state->options->dataset); } $virtualqtype = $this->get_virtual_qtype(); @@ -456,11 +719,11 @@ class question_calculated_qtype extends question_dataset_dependent_questiontype } foreach ($numericalquestion->options->answers as $key => $answer) { $answer = &$numericalquestion->options->answers[$key]; // for PHP 4.x - $answer->answer = $this->substitute_variables($answer->answer, + $answer->answer = $this->substitute_variables_and_eval($answer->answer, $state->options->dataset); // apply_unit } - $numericalquestion->questiontext = $this->substitute_variables( + $numericalquestion->questiontext = $this->substitute_variables_and_eval( $numericalquestion->questiontext, $state->options->dataset); $responses = $virtualqtype->get_all_responses($numericalquestion, $state); $response = reset($responses->responses); @@ -670,7 +933,6 @@ class question_calculated_qtype extends question_dataset_dependent_questiontype FROM {question_dataset_items} WHERE definition = ? ORDER BY itemnumber", array($datasetdef->id)); } - // echo "
"; print_r($datasetdefs[$defid]->items);
                 for ($numberadded =$maxnumber+1 ; $numberadded <= $maxnumber+$numbertoadd ; $numberadded++){
                     if (isset($datasetdefs[$defid]->items[$numberadded]) && ! $regenerate ){
                         //  echo "
Reuse an previously used record".$numberadded."id".$datasetdef->id."
";
@@ -683,7 +945,6 @@ class question_calculated_qtype extends question_dataset_dependent_questiontype
                         } else {
                             $datasetitem->value = '';
                         }
-                        //pp  echo "
"; print_r( $datasetitem );
                         if (!$DB->insert_record('question_dataset_items', $datasetitem)) {
                             print_error('cannotinsert', 'question');
                         }
@@ -772,7 +1033,7 @@ class question_calculated_qtype extends question_dataset_dependent_questiontype
         $virtualqtype = $this->get_virtual_qtype();
         foreach ($answers as $answer) {
           //  $formula = $answer->answer;
-            $formula = parent::substitute_variables($answer->answer,$data);
+            $formula = $this->substitute_variables($answer->answer,$data);
           /*  foreach ($data as $name => $value) {
                 $formula = str_replace('{'.$name.'}', $value, $formula);
             }*/
@@ -814,17 +1075,17 @@ class question_calculated_qtype extends question_dataset_dependent_questiontype
     // filters options that are currently not accepted by calculated
     // It also determines a default selection...
     //$renameabledatasets not implemented anmywhere
-        list($options, $selected) = parent::dataset_options($form, $name,'','qtype_calculated');
+        list($options, $selected) = $this->dataset_options_from_database($form, $name,'','qtype_calculated');
   //  list($options, $selected) = $this->dataset_optionsa($form, $name);
 
         foreach ($options as $key => $whatever) {
-            if (!ereg('^'.LITERAL.'-', $key) && $key != '0') {
+            if (!ereg('^1-', $key) && $key != '0') {
                 unset($options[$key]);
             }
         }
         if (!$selected) {
             if ($mandatory){
-            $selected = LITERAL . "-0-$name"; // Default
+            $selected =  "1-0-$name"; // Default
             }else {
                 $selected = "0"; // Default
             }
@@ -880,8 +1141,21 @@ class question_calculated_qtype extends question_dataset_dependent_questiontype
     }
 
     function substitute_variables($str, $dataset) {
-        $formula = parent::substitute_variables($str, $dataset);
-        if ($error = qtype_calculated_find_formula_errors($formula)) {
+          //  print_r(
+
+        foreach ($dataset as $name => $value) {
+            if($value < 0 ){
+                $str = str_replace('{'.$name.'}', '('.$value.')', $str);
+            } else {
+                $str = str_replace('{'.$name.'}', $value, $str);
+            }
+        }
+        return $str;
+    }
+
+    function substitute_variables_and_eval($str, $dataset) {
+        $formula = $this->substitute_variables($str, $dataset) ;
+       if ($error = qtype_calculated_find_formula_errors($formula)) {
             return $error;
         }
         /// Calculate the correct answer
@@ -893,6 +1167,309 @@ class question_calculated_qtype extends question_dataset_dependent_questiontype
         return $str;
     }
 
+    function get_dataset_definitions($questionid, $newdatasets) {
+        global $DB;
+        //get the existing datasets for this question
+        $datasetdefs = array();
+        if (!empty($questionid)) {
+            global $CFG;
+            $sql = "SELECT i.*
+                    FROM {question_datasets} d,
+                         {question_dataset_definitions} i
+                    WHERE d.question = ?
+                    AND   d.datasetdefinition = i.id
+                   ";
+            if ($records = $DB->get_records_sql($sql, array($questionid))) {
+                foreach ($records as $r) {
+                    $datasetdefs["$r->type-$r->category-$r->name"] = $r;
+                }
+            }
+        }
+
+        foreach ($newdatasets as $dataset) {
+            if (!$dataset) {
+                continue; // The no dataset case...
+            }
+
+            if (!isset($datasetdefs[$dataset])) {
+                //make new datasetdef
+                list($type, $category, $name) = explode('-', $dataset, 3);
+                $datasetdef = new stdClass;
+                $datasetdef->type = $type;
+                $datasetdef->name = $name;
+                $datasetdef->category  = $category;
+                $datasetdef->itemcount = 0;
+                $datasetdef->options   = 'uniform:1.0:10.0:1';
+                $datasetdefs[$dataset] = clone($datasetdef);
+            }
+        }
+        return $datasetdefs;
+    }
+
+    function save_dataset_definitions($form) {
+        global $DB;
+        // Save datasets
+        $datasetdefinitions = $this->get_dataset_definitions($form->id, $form->dataset);
+        $tmpdatasets = array_flip($form->dataset);
+        $defids = array_keys($datasetdefinitions);
+        foreach ($defids as $defid) {
+            $datasetdef = &$datasetdefinitions[$defid];
+            if (isset($datasetdef->id)) {
+                if (!isset($tmpdatasets[$defid])) {
+                // This dataset is not used any more, delete it
+                    $DB->delete_records('question_datasets', array('question' => $form->id, 'datasetdefinition' => $datasetdef->id));
+                    if ($datasetdef->category == 0) { // Question local dataset
+                        $DB->delete_records('question_dataset_definitions', array('id' => $datasetdef->id));
+                        $DB->delete_records('question_dataset_items', array('definition' => $datasetdef->id));
+                    }
+                }
+                // This has already been saved or just got deleted
+                unset($datasetdefinitions[$defid]);
+                continue;
+            }
+
+            if (!$datasetdef->id = $DB->insert_record('question_dataset_definitions', $datasetdef)) {
+                print_error("cannotcreatedataset", 'question', '', $defid);
+            }
+
+            if (0 != $datasetdef->category) {
+                // We need to look for already existing
+                // datasets in the category.
+                // By first creating the datasetdefinition above we
+                // can manage to automatically take care of
+                // some possible realtime concurrence
+                if ($olderdatasetdefs = $DB->get_records_select( 'question_dataset_definitions',
+                        "type = ?
+                        AND name = ?
+                        AND category = ?
+                        AND id < ?
+                        ORDER BY id DESC", array($datasetdef->type, $datasetdef->name, $datasetdef->category, $datasetdef->id))) {
+
+                    while ($olderdatasetdef = array_shift($olderdatasetdefs)) {
+                        $DB->delete_records('question_dataset_definitions', array('id' => $datasetdef->id));
+                        $datasetdef = $olderdatasetdef;
+                    }
+                }
+            }
+
+            // Create relation to this dataset:
+            $questiondataset = new stdClass;
+            $questiondataset->question = $form->id;
+            $questiondataset->datasetdefinition = $datasetdef->id;
+            if (!$DB->insert_record('question_datasets', $questiondataset)) {
+                print_error('cannotcreaterelation', 'question', '', $name);
+            }
+            unset($datasetdefinitions[$defid]);
+        }
+
+        // Remove local obsolete datasets as well as relations
+        // to datasets in other categories:
+        if (!empty($datasetdefinitions)) {
+            foreach ($datasetdefinitions as $def) {
+                $DB->delete_records('question_datasets', array('question' => $form->id, 'datasetdefinition' => $def->id));
+
+                if ($def->category == 0) { // Question local dataset
+                    $DB->delete_records('question_dataset_definitions', array('id' => $def->id));
+                    $DB->delete_records('question_dataset_items', array('definition' => $def->id));
+                }
+            }
+        }
+    }
+    /** This function create a copy of the datasets ( definition and dataitems)
+    * from the preceding question if they remain in the new question
+    * otherwise its create the datasets that have been added as in the
+    * save_dataset_definitions()
+    */
+    function save_as_new_dataset_definitions($form, $initialid) {
+    global $CFG, $DB;
+        // Get the datasets from the intial question
+        $datasetdefinitions = $this->get_dataset_definitions($initialid, $form->dataset);
+        // $tmpdatasets contains those of the new question
+        $tmpdatasets = array_flip($form->dataset);
+        $defids = array_keys($datasetdefinitions);// new datasets
+        foreach ($defids as $defid) {
+            $datasetdef = &$datasetdefinitions[$defid];
+            if (isset($datasetdef->id)) {
+                // This dataset exist in the initial question
+                if (!isset($tmpdatasets[$defid])) {
+                    // do not exist in the new question so ignore
+                    unset($datasetdefinitions[$defid]);
+                    continue;
+                }
+                // create a copy but not for category one
+                if (0 == $datasetdef->category) {
+                   $olddatasetid = $datasetdef->id ;
+                   $olditemcount = $datasetdef->itemcount ;
+                   $datasetdef->itemcount =0;
+                   if (!$datasetdef->id = $DB->insert_record('question_dataset_definitions', $datasetdef)) {
+                        print_error('cannotcreatedataset', 'question', '', $defid);
+                   }
+                   //copy the dataitems
+                   $olditems = $DB->get_records_sql( // Use number as key!!
+                        " SELECT itemnumber, value
+                          FROM {question_dataset_items}
+                          WHERE definition =  ? ", array($olddatasetid));
+                   if (count($olditems) > 0 ) {
+                        $itemcount = 0;
+                        foreach($olditems as $item ){
+                            $item->definition = $datasetdef->id;
+                        if (!$DB->insert_record('question_dataset_items', $item)) {
+                            print_error('cannotinsertitem', 'question', '', array($item->itemnumber, $item->value, $datasetdef->name));
+                        }
+                        $itemcount++;
+                        }
+                        //update item count
+                        $datasetdef->itemcount =$itemcount;
+                        $DB->update_record('question_dataset_definitions', $datasetdef);
+                    } // end of  copy the dataitems
+                }// end of  copy the datasetdef
+                // Create relation to the new question with this
+                // copy as new datasetdef from the initial question
+                $questiondataset = new stdClass;
+                $questiondataset->question = $form->id;
+                $questiondataset->datasetdefinition = $datasetdef->id;
+                if (!$DB->insert_record('question_datasets', $questiondataset)) {
+                    print_error('cannotcreaterelation', 'question', '', $name);
+                }
+                unset($datasetdefinitions[$defid]);
+                continue;
+            }// end of datasetdefs from the initial question
+            // really new one code similar to save_dataset_definitions()
+            if (!$datasetdef->id = $DB->insert_record('question_dataset_definitions', $datasetdef)) {
+                print_error('cannotcreatedataset', 'question', '', $defid);
+            }
+
+            if (0 != $datasetdef->category) {
+                // We need to look for already existing
+                // datasets in the category.
+                // By first creating the datasetdefinition above we
+                // can manage to automatically take care of
+                // some possible realtime concurrence
+                if ($olderdatasetdefs = $DB->get_records_select(
+                        'question_dataset_definitions',
+                        "type = ?
+                        AND name = ?
+                        AND category = ?
+                        AND id < ?
+                        ORDER BY id DESC", array($datasetdef->type, $datasetdef->name, $datasetdef->category, $datasetdef->id))) {
+
+                    while ($olderdatasetdef = array_shift($olderdatasetdefs)) {
+                        $DB->delete_records('question_dataset_definitions', array('id' => $datasetdef->id));
+                        $datasetdef = $olderdatasetdef;
+                    }
+                }
+            }
+
+            // Create relation to this dataset:
+            $questiondataset = new stdClass;
+            $questiondataset->question = $form->id;
+            $questiondataset->datasetdefinition = $datasetdef->id;
+            if (!$DB->insert_record('question_datasets', $questiondataset)) {
+                print_error('cannotcreaterelation', 'question', '', $name);
+            }
+            unset($datasetdefinitions[$defid]);
+        }
+
+        // Remove local obsolete datasets as well as relations
+        // to datasets in other categories:
+        if (!empty($datasetdefinitions)) {
+            foreach ($datasetdefinitions as $def) {
+                $DB->delete_records('question_datasets', array('question' => $form->id, 'datasetdefinition' => $def->id));
+
+                if ($def->category == 0) { // Question local dataset
+                    $DB->delete_records('question_dataset_definitions', array('id' => $def->id));
+                    $DB->delete_records('question_dataset_items', array('definition' => $def->id));
+                }
+            }
+        }
+    }
+
+/// Dataset functionality
+    function pick_question_dataset($question, $datasetitem) {
+        // Select a dataset in the following format:
+        // An array indexed by the variable names (d.name) pointing to the value
+        // to be substituted
+        global $CFG, $DB;
+        if (!$dataset = $DB->get_records_sql(
+                        "SELECT d.name, i.value
+                        FROM {question_dataset_definitions} d,
+                             {question_dataset_items} i,
+                             {question_datasets} q
+                        WHERE q.question = ?
+                        AND q.datasetdefinition = d.id
+                        AND d.id = i.definition
+                        AND i.itemnumber = ?", array($question->id, $datasetitem))) {
+            print_error('cannotgetdsfordependent', 'question', '', array($question->id, $datasetitem));
+        }
+        array_walk($dataset, create_function('&$val', '$val = $val->value;'));
+        return $dataset;
+    }
+    
+    function dataset_options_from_database($form, $name,$prefix='',$langfile='quiz') {
+
+        // First options - it is not a dataset...
+        $options['0'] = get_string($prefix.'nodataset', $langfile);
+
+        // Construct question local options
+        global $CFG, $DB;
+        $currentdatasetdef = $DB->get_record_sql(
+                "SELECT a.*
+                   FROM {question_dataset_definitions} a,
+                        {question_datasets} b
+                  WHERE a.id = b.datasetdefinition
+                    AND b.question = ?
+                    AND a.name = ?", array($form->id, $name))
+        or $currentdatasetdef->type = '0';
+        foreach (array( LITERAL, FILE, LINK) as $type) {
+            $key = "$type-0-$name";
+            if ($currentdatasetdef->type == $type
+                    and $currentdatasetdef->category == 0) {
+                $options[$key] = get_string($prefix."keptlocal$type", $langfile);
+            } else {
+                $options[$key] = get_string($prefix."newlocal$type", $langfile);
+            }
+        }
+
+        // Construct question category options
+        $categorydatasetdefs = $DB->get_records_sql(
+                "SELECT a.type, a.id
+                   FROM {question_dataset_definitions} a,
+                        {question_datasets} b
+                  WHERE a.id = b.datasetdefinition
+                    AND a.category = ?
+                    AND a.name = ?", array($form->category, $name));
+        foreach(array( LITERAL, FILE, LINK) as $type) {
+            $key = "$type-$form->category-$name";
+            if (isset($categorydatasetdefs[$type])
+                    and $categorydef = $categorydatasetdefs[$type]) {
+                if ($currentdatasetdef->type == $type
+                        and $currentdatasetdef->id == $categorydef->id) {
+                    $options[$key] = get_string($prefix."keptcategory$type", $langfile);
+                } else {
+                    $options[$key] = get_string($prefix."existingcategory$type", $langfile);
+                }
+            } else {
+                $options[$key] = get_string($prefix."newcategory$type", $langfile);
+            }
+        }
+
+        // All done!
+        return array($options, $currentdatasetdef->type
+                ? "$currentdatasetdef->type-$currentdatasetdef->category-$name"
+                : '');
+    }
+
+    function find_dataset_names($text) {
+    /// Returns the possible dataset names found in the text as an array
+    /// The array has the dataset name for both key and value
+        $datasetnames = array();
+        while (ereg('\\{([[:alpha:]][^>} <{"\']*)\\}', $text, $regs)) {
+            $datasetnames[$regs[1]] = $regs[1];
+            $text = str_replace($regs[0], '', $text);
+        }
+        return $datasetnames;
+    }
+
     /**
     * This function retrieve the item count of the available category shareable
     * wild cards that is added as a comment displayed when a wild card with
@@ -985,6 +1562,12 @@ class question_calculated_qtype extends question_dataset_dependent_questiontype
         }
         return  $text ;
     }
+    function get_virtual_qtype() {
+        if (!$this->virtualqtype) {
+            $this->virtualqtype = $this->create_virtual_qtype();
+        }
+        return $this->virtualqtype;
+    }
 
 
 /// BACKUP FUNCTIONS ////////////////////////////
@@ -1153,7 +1736,7 @@ function qtype_calculated_calculate_answer($formula, $individualdata,
 
     /// Exchange formula variables with the correct values...
     global $QTYPES;
-    $answer = $QTYPES['calculated']->substitute_variables($formula, $individualdata);
+    $answer = $QTYPES['calculated']->substitute_variables_and_eval($formula, $individualdata);
     if ('1' == $answerformat) { /* Answer is to have $answerlength decimals */
         /*** Adjust to the correct number of decimals ***/
         if (stripos($answer,'e')>0 ){
-- 
2.39.5