Further work on plugging STACK into Moodle.

question.php

@@ -39,6 +39,11 @@ require_once(dirname(__FILE__) . '/stack/potentialresponsetree.class.php');
  */
 class qtype_stack_question extends question_graded_automatically {
 
+    /**
+     * @var int STACK specific: seeds Maxima's random number generator.
+     */
+    public $seed;
+
     /**
      * @var array STACK specific: string name as it appears in the question text => stack_interaction_element
      */
@@ -54,6 +59,11 @@ class qtype_stack_question extends question_graded_automatically {
      */
     public $prts;
 
+    /**
+     * @var array stack_cas_session STACK specific: session of variables.
+     */
+    public $session;
+
     /**
      * @var stack_options STACK specific: question-level options.
      */
@@ -67,20 +77,24 @@ class qtype_stack_question extends question_graded_automatically {
         $questionvars = new stack_cas_keyval($this->questionvariables, $this->options, $seed, 't');
         $qtext = new stack_cas_text($this->questiontext, $questionvars->get_session(), $seed, 't', false, true);
 
-        //HACK - this represents my confusion between "question" and "render"...
         $this->questiontext = $qtext->get_display_castext();
+        $this->session = $qtext->get_session();
         $step->set_qt_var('_questiontext', $qtext->get_display_castext());
-        $step->set_qt_var('_questiontext', $qtext->get_display_castext());
+        $step->set_qt_var('_session', $qtext->get_session());
 
         if ($qtext->get_errors()) {
             //TODO better error trapping that this.
             throw new Exception('Error rendering question text: ' . $qtext->get_errors());
         }
 
+        //$generalfeedback = new stack_cas_text($this->generalfeedback, $this->session, $seed, 't', false, true);
+        //$this->generalfeedback = $generalfeedback->get_display_castext();
     }
 
     public function apply_attempt_state(question_attempt_step $step) {
-        // TODO
+        $this->seed         = $step->get_qt_var('_seed');
+        $this->questiontext = $step->get_qt_var('_questiontext');
+        $this->session      = $step->get_qt_var('_session');
     }
 
     public function get_expected_data() {
@@ -96,7 +110,7 @@ class qtype_stack_question extends question_graded_automatically {
     }
 
     public function get_correct_response() {
-        return null; // TODO can we implement this?
+        return null; // TODO can we implement this?  Yes!  Take the teacher's answer from each interaction element.
     }
 
     public function is_same_response(array $prevresponse, array $newresponse) {

renderer.php

@@ -33,15 +33,18 @@ defined('MOODLE_INTERNAL') || die();
 class qtype_stack_renderer extends qtype_renderer {
     public function formulation_and_controls(question_attempt $qa, question_display_options $options) {
         $question = $qa->get_question();
+        //$response = $question->get_response($qa);
 
-        $questiontext = $question->questiontext; //$question->get_qt_var('_questiontext');
+        $questiontext = $question->questiontext;
+        $seed = 0; // $question->seed;
+        $session = null; // $question->session;
         if (empty($question->interactions)) {
             $xhtml = '<div class="secondaryFeedback">'.stack_string('stackQuestion_noQuestionParts').'</div>'.$questiontext;
         } else {
             foreach ($question->interactions as $name => $interaction) {
-                // TODO: get the value of the current answer to put into the html.
-                $currentanswer = ''; //$qa->get_last_qt_var('answer');
                 $fieldname = $qa->get_qt_field_name($name);
+                $currentanswer = $qa->get_last_qt_var($name);
+                $answers[$name] = $currentanswer;
                 $questiontext = str_replace("#{$name}#",
                 $interaction->get_xhtml($currentanswer, $fieldname, $options->readonly), $questiontext);
 
@@ -54,15 +57,12 @@ class qtype_stack_renderer extends qtype_renderer {
                 // TODO see stack_old/lib/ui/DisplayItem.php.
                 $requirednames = $prt->get_required_variables(array_keys($question->interactions));
                 if ($this->execute_prt($requirednames, $attemptstatus)) {
-                    list($feedback, $answernote, $errors, $valid, $mark, $penalty) = $prt->evaluate_response($questionvars, $options, $answers, $seed);
-                    if (!$valid) {
-                        $penalty = 0;
-                    }
-                    // TODO store the outcomes of the attempt..
-                    // TODO update the mark....
+                    $results = $prt->evaluate_response($session, $question->options, $answers, $seed);
                 } else { // TODO...
-                    $feedback = '';
+                    $results['feedback'] = '';
                 }
+                $feedback = $this->format_prt_feedback($results['feedback']);
+
                 $questiontext = str_replace("<PRTfeedback>{$index}</PRTfeedback>", $feedback, $questiontext);
             }
         }
@@ -70,6 +70,10 @@ class qtype_stack_renderer extends qtype_renderer {
                 $qa, 'question', 'questiontext', $question->id);
     }
 
+private function format_prt_feedback($feedback) {
+        return '<div class="PRTFeedback">'.$feedback.'</div>';
+}
+
     /**
      * Decides if the potential response tree should be executed.
      */

stack/interaction/algebraic.class.php

@@ -25,10 +25,10 @@ class stack_interaction_algebra extends stack_interaction_element {
 
     public function get_xhtml($studentanswer, $fieldname, $readonly) {
         $value = '';
-        if ($studentanswer) {
-            $value = ' value="' . htmlspecialchars($studentanswer) . '"';
-        } else {
+        if (''===trim($studentanswer)) {
             $value = ' value="' . htmlspecialchars($this->parameters['syntaxHint']) . '"';
+        } else {
+            $value = ' value="' . htmlspecialchars($studentanswer) . '"';
         }
 
         $disabled = '';

stack/interaction/simpletest/test.algebraic.class.php

@@ -47,6 +47,12 @@ class stack_interaction_algebra_test extends UnitTestCase {
                 $el->get_xhtml('', 'stack1__ans1', false));
     }
 
+    public function test_get_xhtml_zero() {
+        $el = stack_interaction_controller::make_element('algebraic', 'ans1', '0');
+        $this->assertEqual('<input type="text" name="stack1__ans1" size="15" value="0" />',
+                $el->get_xhtml('0', 'stack1__ans1', false));
+    }
+
     public function test_get_xhtml_pre_filled() {
         $el = stack_interaction_controller::make_element('algebraic', 'test', 'x^2');
         $this->assertEqual('<input type="text" name="stack1__test" size="15" value="x+y" />',

stack/potentialresponsenode.class.php

@@ -152,7 +152,6 @@ class stack_potentialresponse_node {
             $feedback[] = $resultbranch['feedback'];
         }
 
-        $this->result = $result;
         return array(
             'result' => $result,
             'valid' => $at->get_at_valid(),
@@ -236,7 +235,7 @@ class stack_potentialresponse_node {
 
             default:
                 throw new Exception('stack_potentialresponse_node: update_mark called ' .
-                        'with invalid mark modificiation method: ' . $markmodification);
+                        'with invalid mark modificiation method: ' . $resultbranch['markmodification']);
         }
     }