MDL-57368 templates: add example context to core_form/element-template

theme/boost/templates/core_form/element-template.mustache

@@ -1,3 +1,46 @@
+{{!
+    This file is part of Moodle - http://moodle.org/
+
+    Moodle is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Moodle is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+}}
+{{!
+    @template core_form/element-template
+
+    Template for the form element wrapper template.
+
+    Context variables required for this template:
+    * label
+    * required
+    * advanced
+    * helpbutton
+    * error
+    * element
+        * id
+        * name
+
+    Example context (json):
+    {
+        "label": "Course full name",
+        "required": true,
+        "advanced": false,
+        "error": null,
+        "element": {
+            "id": "id_fullname",
+            "name": "fullname"
+        }
+    }
+}}
 <div class="form-group row {{#error}}has-danger{{/error}} fitem {{#advanced}}advanced{{/advanced}} {{{element.extraclasses}}}">
     <div class="col-md-3">
         <span class="pull-xs-right text-nowrap">