Fix get_expected_data for the matrix input type.

This requires re-working how input elements can adjust themselves based
on the teacher's model answer, but I think this is an improvement.

question.php

@@ -260,6 +260,9 @@ class qtype_stack_question extends question_graded_automatically_with_countback
         // Finally, store only those values really needed for later.
         $session->prune_session($session_length);
         $this->session = $session;
+
+        // Allow inputs to update themselves based on the model answers.
+        $this->adapt_inputs();
     }
 
     public function apply_attempt_state(question_attempt_step $step) {
@@ -267,6 +270,18 @@ class qtype_stack_question extends question_graded_automatically_with_countback
         $questionvars = new stack_cas_keyval($step->get_qt_var('_questionvars'), $this->options, $this->seed, 't');
         $this->session = $questionvars->get_session();
         $this->questionnoteinstantiated = $step->get_qt_var('_questionnote');
+        $this->adapt_inputs();
+    }
+
+    /**
+     * Give all the input elements a chance to configure themselves given the
+     * teacher's model answers.
+     */
+    protected function adapt_inputs() {
+        foreach ($this->inputs as $name => $input) {
+            $teacheranswer = $this->session->get_value_key($name);
+            $input->adapt_to_model_answer($teacheranswer);
+        }
     }
 
     public function format_generalfeedback($qa) {
@@ -286,11 +301,8 @@ class qtype_stack_question extends question_graded_automatically_with_countback
 
     public function get_expected_data() {
         $expected = array();
-        foreach ($this->inputs as $name => $input) {
-            $expected[$name] = PARAM_RAW;
-            if ($input->requires_validation()) {
-                $expected[$name . '_val'] = PARAM_RAW;
-            }
+        foreach ($this->inputs as $input) {
+            $expected += $input->get_expected_data();
         }
         return $expected;
     }

renderer.php

@@ -47,7 +47,7 @@ class qtype_stack_renderer extends qtype_renderer {
             $state = $question->get_input_state($name, $response);
 
             $questiontext = str_replace("[[input:{$name}]]",
-                    $input->render($state, $qa->get_qt_field_name($name), $options->readonly, $question->get_session_variable($name)),
+                    $input->render($state, $qa->get_qt_field_name($name), $options->readonly),
                     $questiontext);
 
             $feedback = $this->input_validation($name, $input->render_validation($state, $qa->get_qt_field_name($name)));

stack/input/algebraic/algebraic.class.php

@@ -23,7 +23,7 @@
  */
 class stack_algebraic_input extends stack_input {
 
-    public function render(stack_input_state $state, $fieldname, $readonly, $teachersanswer) {
+    public function render(stack_input_state $state, $fieldname, $readonly) {
         $attributes = array(
             'type' => 'text',
             'name' => $fieldname,

stack/input/algebraic/tests/algebraic_test.php

@@ -45,42 +45,42 @@ class stack_algebra_input_test extends qtype_stack_testcase {
         $el = stack_input_factory::make('algebraic', 'ans1', 'x^2');
         $this->assertEquals('<input type="text" name="stack1__ans1" size="15" value="" />',
                 $el->render(new stack_input_state(stack_input::VALID, '', '', '', ''),
-                        'stack1__ans1', false, ''));
+                        'stack1__ans1', false));
     }
 
     public function test_render_zero() {
         $el = stack_input_factory::make('algebraic', 'ans1', '0');
         $this->assertEquals('<input type="text" name="stack1__ans1" size="15" value="0" />',
                 $el->render(new stack_input_state(stack_input::VALID, '0', '', '', ''),
-                        'stack1__ans1', false, ''));
+                        'stack1__ans1', false));
     }
 
     public function test_render_pre_filled() {
         $el = stack_input_factory::make('algebraic', 'test', 'x^2');
         $this->assertEquals('<input type="text" name="stack1__test" size="15" value="x+y" />',
                 $el->render(new stack_input_state(stack_input::VALID, 'x+y', '', '', ''),
-                        'stack1__test', false, ''));
+                        'stack1__test', false));
     }
 
     public function test_render_pre_filled_nasty_input() {
         $el = stack_input_factory::make('algebraic', 'test', 'x^2');
         $this->assertEquals('<input type="text" name="stack1__test" size="15" value="x&lt;y" />',
                 $el->render(new stack_input_state(stack_input::VALID, 'x<y', '', '', ''),
-                        'stack1__test', false, ''));
+                        'stack1__test', false));
     }
 
     public function test_render_max_length() {
         $el = stack_input_factory::make('algebraic', 'test', 'x^2');
         $this->assertEquals('<input type="text" name="stack1__test" size="15" value="x+y" />',
                 $el->render(new stack_input_state(stack_input::VALID, 'x+y', '', '', ''),
-                        'stack1__test', false, ''));
+                        'stack1__test', false));
     }
 
     public function test_render_disabled() {
         $el = stack_input_factory::make('algebraic', 'input', 'x^2');
         $this->assertEquals('<input type="text" name="stack1__input" size="15" value="x+1" readonly="readonly" />',
                 $el->render(new stack_input_state(stack_input::VALID, 'x+1', '', '', ''),
-                        'stack1__input', true, ''));
+                        'stack1__input', true));
     }
 
     public function test_render_different_size() {
@@ -88,7 +88,7 @@ class stack_algebra_input_test extends qtype_stack_testcase {
         $el->set_parameter('boxWidth', 30);
         $this->assertEquals('<input type="text" name="stack1__input" size="30" value="x+1" />',
                 $el->render(new stack_input_state(stack_input::VALID, 'x+1', '', '', ''),
-                        'stack1__input', false, ''));
+                        'stack1__input', false));
     }
 
     public function test_render_syntaxhint() {
@@ -96,7 +96,7 @@ class stack_algebra_input_test extends qtype_stack_testcase {
         $el->set_parameter('syntaxHint', '[?, ?, ?]');
         $this->assertEquals('<input type="text" name="stack1__sans1" size="15" value="[?, ?, ?]" />',
                 $el->render(new stack_input_state(stack_input::BLANK, '', '', '', ''),
-                        'stack1__sans1', false, ''));
+                        'stack1__sans1', false));
     }
 
     public function test_validate_student_response_1() {

stack/input/boolean/boolean.class.php

@@ -40,7 +40,7 @@ class stack_boolean_input extends stack_input {
         );
     }
 
-    public function render(stack_input_state $state, $fieldname, $readonly, $teachersanswer) {
+    public function render(stack_input_state $state, $fieldname, $readonly) {
 
         $attributes = array();
         if ($readonly) {

stack/input/boolean/tests/boolean_test.php

@@ -57,21 +57,21 @@ class stack_boolean_input_rendering_test extends question_testcase {
         $el = stack_input_factory::make('boolean', 'ans2', stack_boolean_input::T);
         $this->assert(new question_contains_select_expectation('stack1__ans2', $this->expected_choices(),
                 stack_boolean_input::T), $el->render(new stack_input_state(stack_input::VALID, stack_boolean_input::T, '', '', ''),
-                        'stack1__ans2', false, ''));
+                        'stack1__ans2', false));
     }
 
     public function test_render_false() {
         $el = stack_input_factory::make('boolean', 'ans3', stack_boolean_input::T);
         $this->assert(new question_contains_select_expectation('stack1__ans3', $this->expected_choices(),
                 stack_boolean_input::F), $el->render(new stack_input_state(stack_input::VALID, stack_boolean_input::F, '', '', ''),
-                        'stack1__ans3', false, ''));
+                        'stack1__ans3', false));
     }
 
     public function test_render_disabled() {
         $el = stack_input_factory::make('boolean', 'input', stack_boolean_input::T);
         $this->assert(new question_contains_select_expectation('stack1__ans1', $this->expected_choices(),
                 stack_boolean_input::NA, false), $el->render(new stack_input_state(stack_input::BLANK, '', '', '', ''),
-                        'stack1__ans1', true, ''));
+                        'stack1__ans1', true));
     }
 }
 

stack/input/dropdown/dropdown.class.php

@@ -43,7 +43,7 @@ class stack_dropdown_input extends stack_input {
         return $choices;
     }
 
-    public function render(stack_input_state $state, $fieldname, $readonly, $teachersanswer) {
+    public function render(stack_input_state $state, $fieldname, $readonly) {
         $values = $this->get_choices();
         if (empty($values)) {
             return stack_string('ddl_empty');

stack/input/inputbase.class.php

@@ -102,6 +102,17 @@ abstract class stack_input {
         }
     }
 
+    /**
+     * This method gives the input element a change to adapt itself given the
+     * value of the teachers model answer for this variant of the question.
+     * For example, the matrix question type uses this to work out how many
+     * rows and columns it should have.
+     * @param string $teacheranswer the teacher's model answer for this input.
+     */
+    public function adapt_to_model_answer($teacheranswer) {
+        // By default, do nothing.
+    }
+
     /**
      * @param string $param a settings parameter name.
      * @return bool whether this input type uses this parameter.
@@ -210,6 +221,20 @@ abstract class stack_input {
         return array();
     }
 
+    /**
+     * Get the input variable that this input expects to process.
+     * All the variable names should start with $this->name.
+     * @return array string input name => PARAM_... type constant.
+     */
+    public function get_expected_data() {
+        $expected = array();
+        $expected[$this->name] = PARAM_RAW;
+        if ($this->requires_validation()) {
+            $expected[$this->name . '_val'] = PARAM_RAW;
+        }
+        return $expected;
+    }
+
     /**
      * @return string the teacher's answer, an example of what could be typed into
      * this input as part of a correct response to the question.
@@ -322,10 +347,9 @@ abstract class stack_input {
      * @param string student's current answer to insert into the xhtml.
      * @param string $fieldname the field name to use in the HTML for this input.
      * @param bool $readonly whether the contro should be displayed read-only.
-     * @param string the value of the teacher's answer, post randomization.  This is needed, e.g. to automatically size the matrix elements.
      * @return string HTML for this input.
      */
-    public abstract function render(stack_input_state $state, $fieldname, $readonly, $teachersanswer);
+    public abstract function render(stack_input_state $state, $fieldname, $readonly);
 
     /**
      * Add this input the MoodleForm, but only used in questiontestform.php.

stack/input/matrix/matrix.class.php

@@ -22,32 +22,62 @@
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 class stack_matrix_input extends stack_input {
+    protected $errors = null;
+    protected $width;
+    protected $height;
 
-    public function render(stack_input_state $state, $fieldname, $readonly, $teacheranswer) {
-        $attributes = array(
-            'type' => 'text',
-            'name' => $fieldname,
-        );
+    public function adapt_to_model_answer($teacheranswer) {
 
         // Work out how big the matrix should be from the INSTANTIATED VALUE of the teacher's answer.
         $cs =  new stack_cas_casstring('ta:matrix_size(' . $teacheranswer . ')');
         $cs->validate('t');
         $at1 = new stack_cas_session(array($cs), null, 0);
         $at1->instantiate();
+
         if ('' != $at1->get_errors()) {
-            // If there are errors, don't try to display anything else.
-            return html_writer::tag('p', $at1->get_errors(), array('id' => 'error', 'class' => 'p'));
+            $this->errors = $at1->get_errors();
+            return;
         }
 
         $size = $at1->get_value_key('ta');
         $dimensions = explode(',', $size);
 
-        $height = trim($dimensions[0], '[]');
-        $width = trim($dimensions[1], '[]');
+        $this->height = trim($dimensions[0], '[]');
+        $this->width = trim($dimensions[1], '[]');
+    }
+
+    public function get_expected_data() {
+        $expected = array();
+
+        // All the matrix elements.
+        for ($i = 0; $i < $this->height; $i++)  {
+            for ($j = 0; $j < $this->width; $j++) {
+                $expected[$this->name . '_sub_' . $i . '_' . $j] = PARAM_RAW;
+            }
+        }
+
+        // I am assuming that the valdiation will write one CAS string in a
+        // hidden input, that is the combination of all the separate inputs.
+        if ($this->requires_validation()) {
+            $expected[$this->name . '_val'] = PARAM_RAW;
+        }
+        return $expected;
+    }
+
+    public function render(stack_input_state $state, $fieldname, $readonly) {
+        $attributes = array(
+            'type' => 'text',
+            'name' => $fieldname,
+        );
+
+        if ($this->errors) {
+            // If there are errors, don't try to display anything else.
+            return html_writer::tag('p', $this->errors, array('id' => 'error', 'class' => 'p'));
+        }
 
         // Build an empty array.
-        $firstrow = array_fill(0, $width, '');
-        $tc       = array_fill(0, $height, $firstrow);
+        $firstrow = array_fill(0, $this->width, '');
+        $tc       = array_fill(0, $this->height, $firstrow);
 
         // Turn the student's answer into a PHP array.
         if ('' != $state->contents) {
@@ -61,24 +91,24 @@ class stack_matrix_input extends stack_input {
 
         // Build the html table to contain these values.
         $xhtml = '<table class="matrixtable" style="display:inline; vertical-align: middle;" border="0" cellpadding="1" cellspacing="0"><tbody>';
-        for ($i=0; $i < $height; $i++)  {
+        for ($i=0; $i < $this->height; $i++)  {
             $xhtml .= '<tr>';
             if($i == 0) {
                 $xhtml .= '<td style="border-width: 2px 0px 0px 2px; padding-top: 0.5em">&nbsp;</td>';
-            } elseif ($i == ($height - 1)) {
+            } elseif ($i == ($this->height - 1)) {
                 $xhtml .= '<td style="border-width: 0px 0px 2px 2px;">&nbsp;</td>';
             } else {
                 $xhtml .= '<td style="border-width: 0px 0px 0px 2px;">&nbsp;</td>';
             }
 
-            for ($j=0; $j < $width; $j++) {
+            for ($j=0; $j < $this->width; $j++) {
                 $name = $fieldname.'_sub_'.$i.'_'.$j;
                 $xhtml .= '<td><input type="text" name="'.$name.'" value="'.$tc[$i][$j].'" size="'.$this->parameters['boxWidth'].'" ></td>';
             }
 
             if ($i == 0) {
                 $xhtml .= '<td style="border-width: 2px 2px 0px 0px; padding-top: 0.5em">&nbsp;</td>';
-            } elseif ($i == ($height - 1)) {
+            } elseif ($i == ($this->height - 1)) {
                 $xhtml .= '<td style="border-width: 0px 2px 2px 0px; padding-bottom: 0.5em">&nbsp;</td>';
             } else {
                 $xhtml .= '<td style="border-width: 0px 2px 0px 0px;">&nbsp;</td>';

stack/input/matrix/tests/matrix_test.php

@@ -37,17 +37,19 @@ class stack_matrix_input_test extends qtype_stack_testcase {
 
     public function test_render_blank() {
         $el = stack_input_factory::make('matrix', 'ans1', 'M');
+        $el->adapt_to_model_answer('matrix([1,2,3],[3,4,5])');
         $this->assertEquals('<table class="matrixtable" style="display:inline; vertical-align: middle;" border="0" cellpadding="1" cellspacing="0"><tbody><tr><td style="border-width: 2px 0px 0px 2px; padding-top: 0.5em">&nbsp;</td><td><input type="text" name="ans1_sub_0_0" value="" size="5" ></td><td><input type="text" name="ans1_sub_0_1" value="" size="5" ></td><td><input type="text" name="ans1_sub_0_2" value="" size="5" ></td><td style="border-width: 2px 2px 0px 0px; padding-top: 0.5em">&nbsp;</td></tr><tr><td style="border-width: 0px 0px 2px 2px;">&nbsp;</td><td><input type="text" name="ans1_sub_1_0" value="" size="5" ></td><td><input type="text" name="ans1_sub_1_1" value="" size="5" ></td><td><input type="text" name="ans1_sub_1_2" value="" size="5" ></td><td style="border-width: 0px 2px 2px 0px; padding-bottom: 0.5em">&nbsp;</td></tr></tbody></table>',
                 $el->render(new stack_input_state(stack_input::VALID, '', '', '', ''),
-                        'ans1', false, 'matrix([1,2,3],[3,4,5])'));
+                        'ans1', false));
     }
 
     public function test_render_no_errors_if_garbled() {
         // If the teacher does not know the right syntax for a matrix, we should
         // not give PHP errors.
         $el = stack_input_factory::make('matrix', 'ans1', 'M');
+        $el->adapt_to_model_answer('[[1,0],[0,1]]');
         $this->assertEquals('<p id="error" class="p"><span class="error">The CAS returned the following error(s):</span><span class="stacksyntaxexample">ta:matrix_size([[1,0],[0,1]])</span> caused the following error: The "\$first" argument of the function "\$matrix_size" must be a matrix </p>',
                 $el->render(new stack_input_state(stack_input::VALID, '', '', '', ''),
-                        'ans1', false, '[[1,0],[0,1]]'));
+                        'ans1', false));
     }
 }

stack/input/singlechar/singlechar.class.php

@@ -26,7 +26,7 @@
  */
 class stack_singlechar_input extends stack_input {
 
-    public function render(stack_input_state $state, $fieldname, $readonly, $teachersanswer) {
+    public function render(stack_input_state $state, $fieldname, $readonly) {
 
         $attributes = array(
             'type'      => 'text',

stack/input/singlechar/tests/singlechar_test.php

@@ -38,20 +38,20 @@ class stack_singlechar_input_test extends basic_testcase {
         $el = stack_input_factory::make('singleChar', 'ans1', null);
         $this->assertEquals('<input type="text" name="question__ans1" size="1" maxlength="1" value="" />',
                 $el->render(new stack_input_state(stack_input::BLANK, '', '', '', ''),
-                        'question__ans1', false, ''));
+                        'question__ans1', false));
     }
 
     public function test_render_pre_filled() {
         $el = stack_input_factory::make('singleChar', 'test', null);
         $this->assertEquals('<input type="text" name="question__ans1" size="1" maxlength="1" value="Y" />',
                 $el->render(new stack_input_state(stack_input::VALID, 'Y', '', '', ''),
-                        'question__ans1', false, ''));
+                        'question__ans1', false));
     }
 
     public function test_render_disabled() {
         $el = stack_input_factory::make('singleChar', 'input', null);
         $this->assertEquals('<input type="text" name="question__stack1" size="1" maxlength="1" value="a" readonly="readonly" />',
                 $el->render(new stack_input_state(stack_input::VALID, 'a', '', '', ''),
-                        'question__stack1', true, ''));
+                        'question__stack1', true));
     }
 }

stack/input/textarea/tests/textarea_test.php

@@ -44,7 +44,7 @@ class stack_textarea_input_test extends basic_testcase {
         $el = stack_input_factory::make('textArea', 'ans1', null);
         $this->assertEquals('<textarea name="st_ans1" rows="5" cols="20"></textarea>',
                 $el->render(new stack_input_state(stack_input::BLANK, '', '', '', ''),
-                        'st_ans1', false, ''));
+                        'st_ans1', false));
     }
 
     public function test_render_pre_filled() {
@@ -52,7 +52,7 @@ class stack_textarea_input_test extends basic_testcase {
         $this->assertEquals('<textarea name="st_ans1" rows="5" cols="20">' .
                 "1\n1/sum([1,3])\nmatrix([1],[2])</textarea>",
                 $el->render(new stack_input_state(stack_input::VALID, "1\n1/sum([1,3])\nmatrix([1],[2])", '', '', ''),
-                        'st_ans1', false, ''));
+                        'st_ans1', false));
     }
 
     public function test_render_pre_syntaxhint() {
@@ -60,14 +60,14 @@ class stack_textarea_input_test extends basic_testcase {
         $this->assertEquals('<textarea name="st_ans1" rows="5" cols="20">' .
                     "y=?\n z=?</textarea>",
         $el->render(new stack_input_state(stack_input::BLANK, '', '', '', ''),
-                            'st_ans1', false, ''));
+                            'st_ans1', false));
     }
 
     public function test_render_disabled() {
         $el = stack_input_factory::make('textArea', 'input', null);
         $this->assertEquals('<textarea name="st_ans1" rows="5" cols="20" readonly="readonly"></textarea>',
                 $el->render(new stack_input_state(stack_input::BLANK, '', '', '', ''),
-                        'st_ans1', true, ''));
+                        'st_ans1', true));
     }
 }
 

stack/input/textarea/textarea.class.php

@@ -26,7 +26,7 @@ require_once(dirname(__FILE__) . '/../../utils.class.php');
  */
 class stack_textarea_input extends stack_input {
 
-    public function render(stack_input_state $state, $fieldname, $readonly, $teachersanswer) {
+    public function render(stack_input_state $state, $fieldname, $readonly) {
         // Note that at the moment, $this->boxHeight and $this->boxWidth are only
         // used as minimums. If the current input is bigger, the box is expanded.