WIP: extract tags from [[todo]] blocks in castext.

adminui/dependencies.php

@@ -323,15 +323,17 @@
         'q.id = o.questionid AND ' .
         $DB->sql_like('o.compiledcache', ':trg') . ';', ['trg' => '%stack_todo%']);
     echo '<h4>Questions containing [[todo]] blocks</h4>';
-    echo '<table><thead><tr><th>Question</th></thead><tbody>';
+    echo '<table><thead><tr><th>Question</th><th>Tags</th></thead><tbody>';
     // Load the whole question, simpler to get the contexts correct that way.
     foreach ($qs as $item) {
         $q = question_bank::load_question($item->questionid);
+        $tags = $q->get_question_todos();
         list($context, $seed, $urlparams) = qtype_stack_setup_question_test_page($q);
         $qurl = qbank_previewquestion\helper::question_preview_url($item->questionid,
                 null, null, null, null, $context);
         echo "<tr><td>" . $q->name . ' ' .
-            $OUTPUT->action_icon($qurl, new pix_icon('t/preview', get_string('preview'))) . '</td></tr>';
+            $OUTPUT->action_icon($qurl, new pix_icon('t/preview', get_string('preview'))) .
+            '</td><td>' . implode(', ', $tags). '<td></tr>';
     }
     echo '</tbody></table>';
 }

question.php

@@ -734,6 +734,19 @@ public function get_question_summary() {
         return stack_string('questionnote_missing');
     }
 
+    public function get_question_todos() {
+        $tags = [];
+        $fields = [$this->questiontext, $this->questionnote, $this->generalfeedback,
+            $this->specificfeedback, $this->questiondescription];
+        foreach ($fields as $field) {
+            $tags = array_merge($tags, castext2_parser_utils::get_todoblocks($field));
+        }
+        // Unique tags, sorted.
+        $tags = array_unique($tags);
+        sort($tags);
+        return $tags;
+    }
+
     public function summarise_response(array $response) {
         // Provide seed information on student's version via the normal moodle quiz report.
         $bits = ['Seed: ' . $this->seed];

stack/cas/castext2/README

@@ -17,17 +17,17 @@ Some key differences to the Abacus era castext:
    step can thus be cached and its result is processable even even without 
    knowing the original code used to generate it.
 
- - '@' and '#' chars are now alloed within {@...@} and {#...#} blocks again due
+ - '@' and '#' chars are now allowed within {@...@} and {#...#} blocks again due
    to the parser grammar being better.
 
- - Mathmode paintting is being done outside the actual parser to simplify 
+ - Mathmode painting is being done outside the actual parser to simplify 
    the parser grammar and to allow them to be tuned separately. The mathmode
    identification logic can now ignore 'comment'-blocks and block parameters
    leading to more logical results.
 
- - Overall there are less steps in the process as the parser grammar now 
+ - Overall there are fewer steps in the process as the parser grammar now 
    actually describes a nested block system and the number of 'special' cases
-   is lesser.
+   is reduced.
 
 
 Like the MaximaParser this parser comes from the UI side of Stateful and is 

stack/cas/castext2/blocks/body.block.php

@@ -20,7 +20,7 @@
 require_once(__DIR__ . '/../../../utils.class.php');
 
 /**
- * A block for dealig with non script content in IFRAMe blocks.
+ * A block for dealing with non script content in IFRAME blocks.
  */
 class stack_cas_castext2_body extends stack_cas_castext2_block {
 

stack/cas/castext2/blocks/todo.block.php

@@ -34,4 +34,15 @@ public function is_flat(): bool {
     public function validate_extract_attributes(): array {
         return [];
     }
+
+    public function extract_todo(): array {
+        $tags = [];
+        foreach (explode(',', $this->params['tags']) as $tag) {
+            $tag = trim($tag);
+            if (!array_key_exists($tag, $tags)) {
+                $tags[$tag] = true;
+            }
+        }
+        return array_keys($tags);
+    }
 }

stack/cas/castext2/utils.php

@@ -67,6 +67,28 @@ public static function get_casstrings(string $castext): array {
         return $css;
     }
 
+    public static function get_todoblocks(string $castext): array {
+        if ($castext === '' || $castext === null) {
+            return [];
+        }
+
+        $ast  = self::parse($castext);
+        $root = stack_cas_castext2_special_root::make($ast);
+        $tags  = [];
+
+        $collecttags = function ($node) use (&$tags) {
+            if (!($node instanceof stack_cas_castext2_todo)) {
+                return true;
+            }
+            foreach ($node->extract_todo() as $tag) {
+                $tags[] = $tag;
+            }
+            return true;
+        };
+        $root->callbackRecurse($collecttags);
+        return $tags;
+    }
+
     // Postprocesses the result from CAS. For those that have not yet fully
     // parsed the response. Does not use the full maximaparser infrastructure
     // as the result is just an list of strings... well should be for all simple