jeff/feature-targeted-feedback

CHANGELOG.rst

@@ -118,6 +118,15 @@ client error are correctly passed through to the client.
 LMS: Improve performance of page load and thread list load for
 discussion tab
 
+Studio: Support targeted feedback, which allows for authors to provide explanations for
+incorrect choice selections for multiple choice question choices that will automatically
+display. These are intended to help steer a student to the correct answer. Thus, they are
+best used for quizzes that allow multiple attempts. To provide targeted feedback, add an
+element called <targetedfeedbackset> right before your <solution> or <solutionset>, and in
+this element, provide a <targetedfeedback> for each feedback. Within <targetedfeedback>
+you can specify your text explanation. Both the <targetedfeedback> and <choice> should have
+the same explanation-id attribute.
+
 LMS: The wiki markup cheatsheet dialog is now accessible to screen readers.
 (LMS-1303)
 

common/lib/capa/capa/capa_problem.py

@@ -34,6 +34,7 @@
 
 from pytz import UTC
 
+
 # dict of tagname, Response Class -- this should come from auto-registering
 response_tag_dict = dict([(x.response_tag, x) for x in responsetypes.__all__])
 
@@ -381,11 +382,93 @@ def get_answer_ids(self):
             answer_ids.append(results.keys())
         return answer_ids
 
+    def tree_using_targeted_feedback(self, tree):
+        """
+        Allows for problem questions to show targeted feedback, which are choice-level explanations.
+        Targeted feedback is automatically visible after a student has submitted their answers.
+
+        The <multiplechoiceresponse> tag must have an attribute 'targeted-feedback':
+          - if so, this method will modify the tree
+          - if not, this method will not modify the tree
+          - if the value is 'alwaysShowCorrectChoiceExplanation', then the correct-choice
+            explanation will be automatically visible too after a student has submitted answers
+
+        Note if the value is 'alwaysShowCorrectChoiceExplanation', you probably want to set
+        the "Show Answer" setting to "Never" because now there's no need for a "Show Answer"
+        button because no solution will show up if you were to click the "Show Answer" button
+        """
+
+        # Note that if there are no questions with targeted feedback, the body of the for loop is not executed
+        for mult_choice_response in tree.xpath('//multiplechoiceresponse[@targeted-feedback]'):
+            show_explanation = mult_choice_response.get('targeted-feedback') == 'alwaysShowCorrectChoiceExplanation'
+
+            # Grab the first choicegroup (there should only be one within each <multiplechoiceresponse> tag)
+            choicegroup = mult_choice_response.xpath('./choicegroup[@type="MultipleChoice"]')[0]
+            choices_list = list(choicegroup.iter('choice'))
+
+            # Find the student answer key that matches our <choicegroup> id
+            student_answer = self.student_answers.get(choicegroup.get('id'))
+            expl_id_for_student_answer = None
+
+            # Keep track of the explanation-id that corresponds to the student's answer
+            # Also, keep track of the solution-id
+            solution_id = None
+            for choice in choices_list:
+                if choice.get('name') == student_answer:
+                    expl_id_for_student_answer = choice.get('explanation-id')
+                if choice.get('correct') == 'true':
+                    solution_id = choice.get('explanation-id')
+
+            # Filter out targetedfeedback that doesn't correspond to the answer the student selected
+            # Note: following-sibling will grab all following siblings, so we just want the first in the list
+            targetedfeedbackset = mult_choice_response.xpath('./following-sibling::targetedfeedbackset')
+            if len(targetedfeedbackset) != 0:
+                targetedfeedbackset = targetedfeedbackset[0]
+                targetedfeedbacks = targetedfeedbackset.xpath('./targetedfeedback')
+                for targetedfeedback in targetedfeedbacks:
+                    # Don't show targeted feedback if the student hasn't answer the problem
+                    # or if the target feedback doesn't match the student's (incorrect) answer
+                    if not self.done or targetedfeedback.get('explanation-id') != expl_id_for_student_answer:
+                        targetedfeedbackset.remove(targetedfeedback)
+
+            # Do not displace the solution under these circumstances
+            if not show_explanation or not self.done:
+                continue
+
+            # The next element should either be <solution> or <solutionset>
+            next_element = targetedfeedbackset.getnext()
+            parent_element = tree
+            solution_element = None
+            if next_element.tag == 'solution':
+                solution_element = next_element
+            elif next_element.tag == 'solutionset':
+                solutions = next_element.xpath('./solution')
+                for solution in solutions:
+                    if solution.get('explanation-id') == solution_id:
+                        parent_element = next_element
+                        solution_element = solution
+
+            # If could not find the solution element, then skip the remaining steps below
+            if solution_element is None:
+                continue
+
+            # Change our correct-choice explanation from a "solution explanation" to within
+            # the set of targeted feedback, which means the explanation will render on the page
+            # without the student clicking "Show Answer" or seeing a checkmark next to the correct choice
+            parent_element.remove(solution_element)
+
+            # Add our solution instead to the targetedfeedbackset and change its tag name
+            solution_element.tag = 'targetedfeedback'
+            targetedfeedbackset.append(solution_element)
+
     def get_html(self):
         '''
         Main method called externally to get the HTML to be rendered for this capa Problem.
         '''
+
+        self.tree_using_targeted_feedback(self.tree)
         html = contextualize_text(etree.tostring(self._extract_html(self.tree)), self.context)
+
         return html
 
     def handle_input_ajax(self, data):
@@ -562,8 +645,7 @@ def _extract_html(self, problemtree):  # private
             # other than to examine .tag to see if it's a string. :(
             return
 
-        if (problemtree.tag == 'script' and problemtree.get('type')
-            and 'javascript' in problemtree.get('type')):
+        if (problemtree.tag == 'script' and problemtree.get('type') and 'javascript' in problemtree.get('type')):
             # leave javascript intact.
             return deepcopy(problemtree)
 

common/lib/capa/capa/customrender.py

@@ -98,3 +98,41 @@ def get_html(self):
         return etree.XML(html)
 
 registry.register(SolutionRenderer)
+
+#-----------------------------------------------------------------------------
+
+
+class TargetedFeedbackRenderer(object):
+    '''
+    A targeted feedback is just a <span>...</span> that is used for displaying an
+    extended piece of feedback to students if they incorrectly answered a question.
+    '''
+    tags = ['targetedfeedback']
+
+    def __init__(self, system, xml):
+        self.system = system
+        self.xml = xml
+
+    def get_html(self):
+        """
+        Return the contents of this tag, rendered to html, as an etree element.
+        """
+
+        html = '<section class="targeted-feedback-span"><span>%s</span></section>' % (
+            etree.tostring(self.xml))
+        try:
+            xhtml = etree.XML(html)
+        except Exception as err:
+            if self.system.DEBUG:
+                msg = '<html><div class="inline-error"><p>Error %s</p>' % (
+                    str(err).replace('<', '&lt;'))
+                msg += ('<p>Failed to construct targeted feedback from <pre>%s</pre></p>' %
+                        html.replace('<', '&lt;'))
+                msg += "</div></html>"
+                log.error(msg)
+                return etree.XML(msg)
+            else:
+                raise
+        return xhtml
+
+registry.register(TargetedFeedbackRenderer)