Merge branch 'master' into feature/tomg/fall-design

2012-08-13 10:26:28 -04:00
parent 7b4cd3e4b3 32924d8bfe
commit 6a50da3d16
26 changed files with 1259 additions and 40 deletions
--- a/common/lib/capa/capa/capa_problem.py
+++ b/common/lib/capa/capa/capa_problem.py
@@ -39,7 +39,7 @@ import responsetypes
 # dict of tagname, Response Class -- this should come from auto-registering
 response_tag_dict = dict([(x.response_tag, x) for x in responsetypes.__all__])

-entry_types = ['textline', 'schematic', 'textbox', 'imageinput', 'optioninput', 'choicegroup', 'radiogroup', 'checkboxgroup', 'filesubmission']
+entry_types = ['textline', 'schematic', 'textbox', 'imageinput', 'optioninput', 'choicegroup', 'radiogroup', 'checkboxgroup', 'filesubmission', 'javascriptinput']
 solution_types = ['solution']    			# extra things displayed after "show answers" is pressed
 response_properties = ["responseparam", "answer"]    	# these get captured as student responses

@@ -154,21 +154,10 @@ class LoncapaProblem(object):
    def get_max_score(self):
        '''
        Return maximum score for this problem.
-        We do this by counting the number of answers available for each question
-        in the problem.  If the Response for a question has a get_max_score() method
-        then we call that and add its return value to the count.  That can be
-        used to give complex problems (eg programming questions) multiple points.
        '''
        maxscore = 0
        for response, responder in self.responders.iteritems():
-            if hasattr(responder, 'get_max_score'):
-                try:
-                    maxscore += responder.get_max_score()
-                except Exception:
-                    log.debug('responder %s failed to properly return from get_max_score()' % responder)  # FIXME
-                    raise
-            else:
-                maxscore += len(self.responder_answers[response])
+            maxscore += responder.get_max_score()
        return maxscore

    def get_score(self):
--- a/common/lib/capa/capa/inputtypes.py
+++ b/common/lib/capa/capa/inputtypes.py
@@ -11,6 +11,7 @@ Module containing the problem elements which render into input objects
 - choicegroup
 - radiogroup
 - checkboxgroup
+- javascriptinput
 - imageinput  (for clickable image)
 - optioninput (for option list)
 - filesubmission (upload a file)
@@ -246,6 +247,34 @@ def checkboxgroup(element, value, status, render_template, msg=''):
    html = render_template("choicegroup.html", context)
    return etree.XML(html)

+@register_render_function
+def javascriptinput(element, value, status, render_template, msg='null'):
+    '''
+    Hidden field for javascript to communicate via; also loads the required
+    scripts for rendering the problem and passes data to the problem.
+    '''
+    eid = element.get('id')
+    params = element.get('params')
+    problem_state = element.get('problem_state')
+    display_class = element.get('display_class')
+    display_file = element.get('display_file')
+    
+    # Need to provide a value that JSON can parse if there is no
+    # student-supplied value yet.
+    if value == "":
+        value = 'null'
+    
+    escapedict = {'"': '&quot;'}
+    value = saxutils.escape(value, escapedict)
+    msg   = saxutils.escape(msg, escapedict)
+    context = {'id': eid, 'params': params, 'display_file': display_file, 
+               'display_class': display_class, 'problem_state': problem_state, 
+               'value': value, 'evaluation': msg,
+               }
+    html = render_template("javascriptinput.html", context)
+    return etree.XML(html)
+
+

@register_render_function
 def textline(element, value, status, render_template, msg=""):
--- a/common/lib/capa/capa/javascript_problem_generator.js
+++ b/common/lib/capa/capa/javascript_problem_generator.js
@@ -0,0 +1,30 @@
+require('coffee-script');
+var importAll = function (modulePath) {
+  module = require(modulePath);
+  for(key in module){
+    global[key] = module[key];
+  }
+}
+
+importAll("mersenne-twister-min");
+importAll("xproblem");
+
+generatorModulePath = process.argv[2];
+dependencies        = JSON.parse(process.argv[3]);
+seed                = process.argv[4];
+params              = JSON.parse(process.argv[5]);
+
+if(seed==null){
+    seed = 4;
+}else{
+    seed = parseInt(seed);
+}
+
+for(var i = 0; i < dependencies.length; i++){
+    importAll(dependencies[i]);
+}
+
+generatorModule = require(generatorModulePath);
+generatorClass  = generatorModule.generatorClass;
+generator = new generatorClass(seed, params);
+console.log(JSON.stringify(generator.generate()));
--- a/common/lib/capa/capa/javascript_problem_grader.js
+++ b/common/lib/capa/capa/javascript_problem_grader.js
@@ -0,0 +1,26 @@
+require('coffee-script');
+var importAll = function (modulePath) {
+  module = require(modulePath);
+  for(key in module){
+    global[key] = module[key];
+  }
+}
+
+importAll("xproblem");
+
+graderModulePath    = process.argv[2];
+dependencies        = JSON.parse(process.argv[3]);
+submission          = JSON.parse(process.argv[4]);
+problemState        = JSON.parse(process.argv[5]);
+params              = JSON.parse(process.argv[6]);
+
+for(var i = 0; i < dependencies.length; i++){
+    importAll(dependencies[i]);
+}
+
+graderModule = require(graderModulePath);
+graderClass  = graderModule.graderClass;
+grader = new graderClass(submission, problemState, params);
+console.log(JSON.stringify(grader.grade()));
+console.log(JSON.stringify(grader.evaluation));
+console.log(JSON.stringify(grader.solution));
--- a/common/lib/capa/capa/responsetypes.py
+++ b/common/lib/capa/capa/responsetypes.py
@@ -17,7 +17,11 @@ import random
 import re
 import requests
 import traceback
+import hashlib
 import abc
+import os
+import subprocess
+import xml.sax.saxutils as saxutils

 # specific library imports
 from calc import evaluator, UndefinedVariable
@@ -71,7 +75,6 @@ class LoncapaResponse(object):

    In addition, these methods are optional:

-      - get_max_score        : if defined, this is called to obtain the maximum score possible for this question
      - setup_response       : find and note the answer input field IDs for the response; called by __init__
      - check_hint_condition : check to see if the student's answers satisfy a particular condition for a hint to be displayed
      - render_html          : render this Response as HTML (must return XHTML compliant string)
@@ -130,6 +133,11 @@ class LoncapaResponse(object):
        if self.max_inputfields == 1:
            self.answer_id = self.answer_ids[0]		# for convenience

+        self.maxpoints = dict()
+        for inputfield in self.inputfields:
+            maxpoints = inputfield.get('points','1') # By default, each answerfield is worth 1 point
+            self.maxpoints.update({inputfield.get('id'): int(maxpoints)})
+
        self.default_answer_map = {}			# dict for default answer map (provided in input elements)
        for entry in self.inputfields:
            answer = entry.get('correct_answer')
@@ -139,6 +147,12 @@ class LoncapaResponse(object):
        if hasattr(self, 'setup_response'):
            self.setup_response()

+    def get_max_score(self):
+        '''
+        Return the total maximum points of all answer fields under this Response
+        '''
+        return sum(self.maxpoints.values())
+
    def render_html(self, renderer):
        '''
        Return XHTML Element tree representation of this Response.
@@ -272,9 +286,190 @@ class LoncapaResponse(object):


 #-----------------------------------------------------------------------------
+
+class JavascriptResponse(LoncapaResponse):
+    '''
+    This response type is used when the student's answer is graded via
+    Javascript using Node.js.
+    '''
+
+    response_tag = 'javascriptresponse'
+    max_inputfields = 1
+    allowed_inputfields = ['javascriptinput']
+
+    def setup_response(self):
+
+        # Sets up generator, grader, display, and their dependencies.
+        self.parse_xml()
+
+        self.compile_display_javascript()
+
+        self.params = self.extract_params()
+
+        if self.generator:
+            self.problem_state = self.generate_problem_state()
+        else:
+            self.problem_state = None
+        
+        self.solution = None
+
+        self.prepare_inputfield()
+    
+    def compile_display_javascript(self):
+
+        latestTimestamp = 0
+        basepath = self.system.filestore.root_path + '/js/'
+        for filename in (self.display_dependencies + [self.display]):
+            filepath = basepath + filename
+            timestamp = os.stat(filepath).st_mtime
+            if timestamp > latestTimestamp:
+                latestTimestamp = timestamp
+        
+        h = hashlib.md5()
+        h.update(self.answer_id + str(self.display_dependencies))
+        compiled_filename = 'compiled/' + h.hexdigest() + '.js'
+        compiled_filepath = basepath + compiled_filename
+
+        if not os.path.exists(compiled_filepath) or os.stat(compiled_filepath).st_mtime < latestTimestamp:
+            outfile = open(compiled_filepath, 'w')
+            for filename in (self.display_dependencies + [self.display]):
+                filepath = basepath + filename
+                infile = open(filepath, 'r')
+                outfile.write(infile.read())
+                outfile.write(';\n')
+                infile.close()
+            outfile.close()
+
+        self.display_filename = compiled_filename
+
+    def parse_xml(self):
+        self.generator_xml = self.xml.xpath('//*[@id=$id]//generator',
+                                            id=self.xml.get('id'))[0]
+
+        self.grader_xml = self.xml.xpath('//*[@id=$id]//grader', 
+                                         id=self.xml.get('id'))[0]
+
+        self.display_xml = self.xml.xpath('//*[@id=$id]//display', 
+                                         id=self.xml.get('id'))[0]
+
+        self.xml.remove(self.generator_xml)
+        self.xml.remove(self.grader_xml)
+        self.xml.remove(self.display_xml)
+
+        self.generator = self.generator_xml.get("src")
+        self.grader = self.grader_xml.get("src")
+        self.display = self.display_xml.get("src")
+
+        if self.generator_xml.get("dependencies"):
+            self.generator_dependencies = self.generator_xml.get("dependencies").split()
+        else:
+            self.generator_dependencies = []
+
+        if self.grader_xml.get("dependencies"):
+            self.grader_dependencies = self.grader_xml.get("dependencies").split()
+        else:
+            self.grader_dependencies = []
+
+        if self.display_xml.get("dependencies"):
+            self.display_dependencies = self.display_xml.get("dependencies").split()
+        else:
+            self.display_dependencies = []
+
+        self.display_class = self.display_xml.get("class")
+    
+    def get_node_env(self):
+
+        js_dir = os.path.join(self.system.filestore.root_path, 'js')
+        tmp_env = os.environ.copy()
+        node_path = self.system.node_path + ":" + os.path.normpath(js_dir)
+        tmp_env["NODE_PATH"] = node_path
+        return tmp_env
+
+
+    def generate_problem_state(self):
+
+        generator_file = os.path.dirname(os.path.normpath(__file__)) + '/javascript_problem_generator.js'
+        output = subprocess.check_output(["node",
+                                          generator_file, 
+                                          self.generator, 
+                                          json.dumps(self.generator_dependencies),
+                                          json.dumps(str(self.system.seed)), 
+                                          json.dumps(self.params)
+                                          ],
+                                          env=self.get_node_env()).strip()
+
+        return json.loads(output)
+
+    def extract_params(self):
+
+        params = {}
+    
+        for param in self.xml.xpath('//*[@id=$id]//responseparam', 
+                                        id=self.xml.get('id')):
+
+            params[param.get("name")] = json.loads(param.get("value"))
+        
+        return params
+
+    def prepare_inputfield(self):
+
+        for inputfield in self.xml.xpath('//*[@id=$id]//javascriptinput', 
+                                        id=self.xml.get('id')):
+
+            escapedict = {'"': '&quot;'}
+
+            encoded_params = json.dumps(self.params)
+            encoded_params = saxutils.escape(encoded_params, escapedict)
+            inputfield.set("params", encoded_params)
+
+            encoded_problem_state = json.dumps(self.problem_state)
+            encoded_problem_state = saxutils.escape(encoded_problem_state,
+                                                    escapedict)
+            inputfield.set("problem_state", encoded_problem_state)
+
+            inputfield.set("display_file",  self.display_filename)
+            inputfield.set("display_class", self.display_class)
+
+    def get_score(self, student_answers):
+        json_submission = student_answers[self.answer_id]
+        (all_correct, evaluation, solution) = self.run_grader(json_submission)
+        self.solution = solution
+        correctness = 'correct' if all_correct else 'incorrect'
+        return CorrectMap(self.answer_id, correctness, msg=evaluation)
+    
+    def run_grader(self, submission):
+        if submission is None or submission == '':
+            submission = json.dumps(None)
+
+        grader_file = os.path.dirname(os.path.normpath(__file__)) + '/javascript_problem_grader.js'
+        outputs = subprocess.check_output(["node",
+                                           grader_file, 
+                                           self.grader, 
+                                           json.dumps(self.grader_dependencies),
+                                           submission, 
+                                           json.dumps(self.problem_state), 
+                                           json.dumps(self.params)
+                                          ],
+                                          env=self.get_node_env()).split('\n')
+
+        all_correct = json.loads(outputs[0].strip())
+        evaluation  = outputs[1].strip()
+        solution    = outputs[2].strip()
+        return (all_correct, evaluation, solution)
+    
+    def get_answers(self):
+        if self.solution is None:
+            (_, _, self.solution) = self.run_grader(None)
+
+        return {self.answer_id: self.solution}
+
+            
+
+#-----------------------------------------------------------------------------
+
 class ChoiceResponse(LoncapaResponse):
    '''
-    This Response type is used when the student chooses from a discrete set of
+    This response type is used when the student chooses from a discrete set of
    choices. Currently, to be marked correct, all "correct" choices must be
    supplied by the student, and no extraneous choices may be included.

@@ -313,6 +508,11 @@ class ChoiceResponse(LoncapaResponse):
    In the above example, radiogroup can be replaced with checkboxgroup to allow
    the student to select more than one choice.

+    TODO: In order for the inputtypes to render properly, this response type
+    must run setup_response prior to the input type rendering. Specifically, the
+    choices must be given names. This behavior seems like a leaky abstraction,
+    and it'd be nice to change this at some point.
+
    '''

    response_tag = 'choiceresponse'
@@ -877,7 +1077,10 @@ class CodeResponse(LoncapaResponse):
                (err, self.answer_id, convert_files_to_filenames(student_answers)))
            raise Exception(err)

-        self.context.update({'submission': unicode(submission)})
+        if is_file(submission):
+            self.context.update({'submission': submission.name})
+        else:
+            self.context.update({'submission': submission})

        # Prepare xqueue request
        #------------------------------------------------------------ 
@@ -924,21 +1127,24 @@ class CodeResponse(LoncapaResponse):

    def update_score(self, score_msg, oldcmap, queuekey):

-        (valid_score_msg, correct, score, msg) = self._parse_score_msg(score_msg) 
+        (valid_score_msg, correct, points, msg) = self._parse_score_msg(score_msg) 
        if not valid_score_msg:
            oldcmap.set(self.answer_id, msg='Error: Invalid grader reply.')
            return oldcmap
        
-        correctness = 'incorrect'
-        if correct:
-            correctness = 'correct'
+        correctness = 'correct' if correct else 'incorrect'

        self.context['correct'] = correctness # TODO: Find out how this is used elsewhere, if any

        # Replace 'oldcmap' with new grading results if queuekey matches.
        #   If queuekey does not match, we keep waiting for the score_msg whose key actually matches
        if oldcmap.is_right_queuekey(self.answer_id, queuekey):
-            oldcmap.set(self.answer_id, correctness=correctness, msg=msg.replace('&nbsp;', '&#160;'), queuekey=None)  # Queuekey is consumed
+            # Sanity check on returned points 
+            if points < 0:
+                points = 0
+            elif points > self.maxpoints[self.answer_id]:
+                points = self.maxpoints[self.answer_id]
+            oldcmap.set(self.answer_id, npoints=points, correctness=correctness, msg=msg.replace('&nbsp;', '&#160;'), queuekey=None)  # Queuekey is consumed
        else:
            log.debug('CodeResponse: queuekey %s does not match for answer_id=%s.' % (queuekey, self.answer_id))

@@ -1361,4 +1567,4 @@ class ImageResponse(LoncapaResponse):
 # TEMPORARY: List of all response subclasses
 # FIXME: To be replaced by auto-registration

-__all__ = [CodeResponse, NumericalResponse, FormulaResponse, CustomResponse, SchematicResponse, ExternalResponse, ImageResponse, OptionResponse, SymbolicResponse, StringResponse, ChoiceResponse, MultipleChoiceResponse, TrueFalseResponse]
+__all__ = [CodeResponse, NumericalResponse, FormulaResponse, CustomResponse, SchematicResponse, ExternalResponse, ImageResponse, OptionResponse, SymbolicResponse, StringResponse, ChoiceResponse, MultipleChoiceResponse, TrueFalseResponse, JavascriptResponse]
--- a/common/lib/capa/capa/templates/javascriptinput.html
+++ b/common/lib/capa/capa/templates/javascriptinput.html
@@ -0,0 +1,10 @@
+<form class="javascriptinput capa_inputtype">
+  <input type="hidden" name="input_${id}" id="input_${id}" class="javascriptinput_input"/>
+    <div class="javascriptinput_data" data-display_class="${display_class}" 
+        data-problem_state="${problem_state}" data-params="${params}" 
+        data-submission="${value}" data-evaluation="${evaluation}">
+    </div>
+    <div class="script_placeholder" data-src="/static/js/${display_file}"></div>
+    <div class="javascriptinput_container"></div>
+</form>
+
--- a/common/lib/xmodule/xmodule/capa_module.py
+++ b/common/lib/xmodule/xmodule/capa_module.py
@@ -464,7 +464,7 @@ class CapaModule(XModule):
                return {'success': msg}
            log.exception("Error in capa_module problem checking")
            raise Exception("error in capa_module")
-
+        
        self.attempts = self.attempts + 1
        self.lcp.done = True

--- a/common/lib/xmodule/xmodule/js/src/capa/display.coffee
+++ b/common/lib/xmodule/xmodule/js/src/capa/display.coffee
@@ -1,4 +1,5 @@
 class @Problem
+
  constructor: (element) ->
    @el = $(element).find('.problems-wrapper')
    @id = @el.data('problem-id')
@@ -52,24 +53,71 @@ class @Problem
  render: (content) ->
    if content
      @el.html(content)
-      @bind()
-      @queueing()
+      @executeProblemScripts () =>
+        @setupInputTypes()
+        @bind()
+        @queueing()
    else
      $.postWithPrefix "#{@url}/problem_get", (response) =>
        @el.html(response.html)
-        @executeProblemScripts()
-        @bind()
-        @queueing()
+        @executeProblemScripts () =>
+          @setupInputTypes()
+          @bind()
+          @queueing()

-  executeProblemScripts: ->
-    @el.find(".script_placeholder").each (index, placeholder) ->
-      s = $("<script>")
-      s.attr("type", "text/javascript")
-      s.attr("src", $(placeholder).attr("data-src"))
+  # TODO add hooks for problem types here by inspecting response.html and doing
+  # stuff if a div w a class is found
+
+  setupInputTypes: =>
+    @el.find(".capa_inputtype").each (index, inputtype) =>
+      classes = $(inputtype).attr('class').split(' ')
+      for cls in classes
+        setupMethod = @inputtypeSetupMethods[cls]
+        setupMethod(inputtype) if setupMethod?
+
+  executeProblemScripts: (callback=null) ->
+
+    placeholders = @el.find(".script_placeholder")
+
+    if placeholders.length == 0
+      callback()
+      return
+
+    completed      = (false for i in [1..placeholders.length])
+    callbackCalled = false
+
+    # This is required for IE8 support.
+    completionHandlerGeneratorIE = (index) =>
+      return () ->
+        if (this.readyState == 'complete' || this.readyState == 'loaded')
+          #completionHandlerGenerator.call(self, index)()
+          completionHandlerGenerator(index)()
+
+    completionHandlerGenerator = (index) =>
+      return () =>
+        allComplete = true
+        completed[index] = true
+        for flag in completed
+          if not flag
+            allComplete = false
+            break
+        if allComplete and not callbackCalled
+          callbackCalled = true
+          callback() if callback?
+
+    placeholders.each (index, placeholder) ->
+      s = document.createElement('script')
+      s.setAttribute('src', $(placeholder).attr("data-src"))
+      s.setAttribute('type', "text/javascript")
+
+      s.onload             = completionHandlerGenerator(index)
+
+      # s.onload does not fire in IE8; this does.
+      s.onreadystatechange = completionHandlerGeneratorIE(index)

      # Need to use the DOM elements directly or the scripts won't execute
      # properly.
-      $('head')[0].appendChild(s[0])
+      $('head')[0].appendChild(s)
      $(placeholder).remove()

  ###
@@ -133,6 +181,9 @@ class @Problem
        @render(response.html)
        @updateProgress response

+  # TODO this needs modification to deal with javascript responses; perhaps we
+  # need something where responsetypes can define their own behavior when show
+  # is called.
  show: =>
    if !@el.hasClass 'showed'
      Logger.log 'problem_show', problem: @id
@@ -182,3 +233,20 @@ class @Problem
    @$(".CodeMirror").each (index, element) ->
      element.CodeMirror.save() if element.CodeMirror.save
    @answers = @inputs.serialize()
+
+  inputtypeSetupMethods:
+    javascriptinput: (element) =>
+
+      data = $(element).find(".javascriptinput_data")
+
+      params        = data.data("params")
+      submission    = data.data("submission")
+      evaluation    = data.data("evaluation")
+      problemState  = data.data("problem_state")
+      displayClass  = window[data.data('display_class')]
+
+      container = $(element).find(".javascriptinput_container")
+      submissionField = $(element).find(".javascriptinput_input")
+
+      display = new displayClass(problemState, submission, evaluation, container, submissionField, params)
+      display.render()
--- a/common/lib/xmodule/xmodule/tests/init.py
+++ b/common/lib/xmodule/xmodule/tests/init.py
@@ -8,6 +8,7 @@
 import unittest
 import os
 import fs
+import json

 import json
 import numpy
@@ -31,10 +32,11 @@ i4xs = ModuleSystem(
    render_template=Mock(),
    replace_urls=Mock(),
    user=Mock(),
-    filestore=fs.osfs.OSFS(os.path.dirname(os.path.realpath(__file__))),
+    filestore=fs.osfs.OSFS(os.path.dirname(os.path.realpath(__file__))+"/test_files"),
    debug=True,
    xqueue={'interface':None, 'callback_url':'/', 'default_queuename': 'testqueue'},
-    is_staff=False
+    is_staff=False,
+    node_path=os.environ.get("NODE_PATH", "/usr/local/lib/node_modules")
 )


@@ -323,7 +325,8 @@ class CodeResponseTest(unittest.TestCase):

                new_cmap = CorrectMap()
                new_cmap.update(old_cmap)
-                new_cmap.set(answer_id=answer_ids[i], correctness=correctness, msg='MESSAGE', queuekey=None)
+                npoints = 1 if correctness=='correct' else 0
+                new_cmap.set(answer_id=answer_ids[i], npoints=npoints, correctness=correctness, msg='MESSAGE', queuekey=None)

                test_lcp.update_score(xserver_msgs[correctness], queuekey=1000 + i)
                self.assertEquals(test_lcp.correct_map.get_dict(), new_cmap.get_dict())
@@ -373,6 +376,19 @@ class ChoiceResponseTest(unittest.TestCase):
        self.assertEquals(test_lcp.grade_answers(test_answers).get_correctness('1_3_1'), 'incorrect')
        self.assertEquals(test_lcp.grade_answers(test_answers).get_correctness('1_4_1'), 'correct')

+class JavascriptResponseTest(unittest.TestCase):
+
+    def test_jr_grade(self):
+        problem_file = os.path.dirname(__file__) + "/test_files/javascriptresponse.xml"
+        coffee_file_path = os.path.dirname(__file__) + "/test_files/js/*.coffee"
+        os.system("coffee -c %s" % (coffee_file_path))
+        test_lcp = lcp.LoncapaProblem(open(problem_file).read(), '1', system=i4xs)
+        correct_answers = {'1_2_1': json.dumps({0: 4})}
+        incorrect_answers = {'1_2_1': json.dumps({0: 5})}
+
+        self.assertEquals(test_lcp.grade_answers(incorrect_answers).get_correctness('1_2_1'), 'incorrect')
+        self.assertEquals(test_lcp.grade_answers(correct_answers).get_correctness('1_2_1'), 'correct')
+
 #-----------------------------------------------------------------------------
 # Grading tests

--- a/common/lib/xmodule/xmodule/tests/test_files/javascriptresponse.xml
+++ b/common/lib/xmodule/xmodule/tests/test_files/javascriptresponse.xml
@@ -0,0 +1,13 @@
+<problem>
+
+<javascriptresponse>
+  <generator src="test_problem_generator.js"/>
+  <grader src="test_problem_grader.js"/>
+  <display class="TestProblemDisplay" src="test_problem_display.js"/>
+  <responseparam name="value" value="4"/>
+  <javascriptinput>
+  </javascriptinput>
+</javascriptresponse>
+
+</problem>
+
--- a/common/lib/xmodule/xmodule/tests/test_files/js/compiled/c9a9cd4242d84c924fe5f8324e9ae79d.js
+++ b/common/lib/xmodule/xmodule/tests/test_files/js/compiled/c9a9cd4242d84c924fe5f8324e9ae79d.js
@@ -0,0 +1,50 @@
+// Generated by CoffeeScript 1.3.3
+(function() {
+  var MinimaxProblemDisplay, root,
+    __hasProp = {}.hasOwnProperty,
+    __extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; };
+
+  MinimaxProblemDisplay = (function(_super) {
+
+    __extends(MinimaxProblemDisplay, _super);
+
+    function MinimaxProblemDisplay(state, submission, evaluation, container, submissionField, parameters) {
+      this.state = state;
+      this.submission = submission;
+      this.evaluation = evaluation;
+      this.container = container;
+      this.submissionField = submissionField;
+      this.parameters = parameters != null ? parameters : {};
+      MinimaxProblemDisplay.__super__.constructor.call(this, this.state, this.submission, this.evaluation, this.container, this.submissionField, this.parameters);
+    }
+
+    MinimaxProblemDisplay.prototype.render = function() {};
+
+    MinimaxProblemDisplay.prototype.createSubmission = function() {
+      var id, value, _ref, _results;
+      this.newSubmission = {};
+      if (this.submission != null) {
+        _ref = this.submission;
+        _results = [];
+        for (id in _ref) {
+          value = _ref[id];
+          _results.push(this.newSubmission[id] = value);
+        }
+        return _results;
+      }
+    };
+
+    MinimaxProblemDisplay.prototype.getCurrentSubmission = function() {
+      return this.newSubmission;
+    };
+
+    return MinimaxProblemDisplay;
+
+  })(XProblemDisplay);
+
+  root = typeof exports !== "undefined" && exports !== null ? exports : this;
+
+  root.TestProblemDisplay = TestProblemDisplay;
+
+}).call(this);
+;
--- a/common/lib/xmodule/xmodule/tests/test_files/js/mersenne-twister-min.js
+++ b/common/lib/xmodule/xmodule/tests/test_files/js/mersenne-twister-min.js
@@ -0,0 +1,202 @@
+/*
+  I've wrapped Makoto Matsumoto and Takuji Nishimura's code in a namespace
+  so it's better encapsulated. Now you can have multiple random number generators
+  and they won't stomp all over eachother's state.
+  
+  If you want to use this as a substitute for Math.random(), use the random()
+  method like so:
+  
+  var m = new MersenneTwister();
+  var randomNumber = m.random();
+  
+  You can also call the other genrand_{foo}() methods on the instance.
+
+  If you want to use a specific seed in order to get a repeatable random
+  sequence, pass an integer into the constructor:
+
+  var m = new MersenneTwister(123);
+
+  and that will always produce the same random sequence.
+
+  Sean McCullough (banksean@gmail.com)
+*/
+
+/* 
+   A C-program for MT19937, with initialization improved 2002/1/26.
+   Coded by Takuji Nishimura and Makoto Matsumoto.
+ 
+   Before using, initialize the state by using init_genrand(seed)  
+   or init_by_array(init_key, key_length).
+ 
+   Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
+   All rights reserved.                          
+ 
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+ 
+     1. Redistributions of source code must retain the above copyright
+        notice, this list of conditions and the following disclaimer.
+ 
+     2. Redistributions in binary form must reproduce the above copyright
+        notice, this list of conditions and the following disclaimer in the
+        documentation and/or other materials provided with the distribution.
+ 
+     3. The names of its contributors may not be used to endorse or promote 
+        products derived from this software without specific prior written 
+        permission.
+ 
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ 
+ 
+   Any feedback is very welcome.
+   http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
+   email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)
+*/
+
+var MersenneTwister = function(seed) {
+  if (seed == undefined) {
+    seed = new Date().getTime();
+  } 
+  /* Period parameters */  
+  this.N = 624;
+  this.M = 397;
+  this.MATRIX_A = 0x9908b0df;   /* constant vector a */
+  this.UPPER_MASK = 0x80000000; /* most significant w-r bits */
+  this.LOWER_MASK = 0x7fffffff; /* least significant r bits */
+ 
+  this.mt = new Array(this.N); /* the array for the state vector */
+  this.mti=this.N+1; /* mti==N+1 means mt[N] is not initialized */
+
+  this.init_genrand(seed);
+}  
+ 
+/* initializes mt[N] with a seed */
+MersenneTwister.prototype.init_genrand = function(s) {
+  this.mt[0] = s >>> 0;
+  for (this.mti=1; this.mti<this.N; this.mti++) {
+      var s = this.mt[this.mti-1] ^ (this.mt[this.mti-1] >>> 30);
+   this.mt[this.mti] = (((((s & 0xffff0000) >>> 16) * 1812433253) << 16) + (s & 0x0000ffff) * 1812433253)
+  + this.mti;
+      /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
+      /* In the previous versions, MSBs of the seed affect   */
+      /* only MSBs of the array mt[].                        */
+      /* 2002/01/09 modified by Makoto Matsumoto             */
+      this.mt[this.mti] >>>= 0;
+      /* for >32 bit machines */
+  }
+}
+ 
+/* initialize by an array with array-length */
+/* init_key is the array for initializing keys */
+/* key_length is its length */
+/* slight change for C++, 2004/2/26 */
+MersenneTwister.prototype.init_by_array = function(init_key, key_length) {
+  var i, j, k;
+  this.init_genrand(19650218);
+  i=1; j=0;
+  k = (this.N>key_length ? this.N : key_length);
+  for (; k; k--) {
+    var s = this.mt[i-1] ^ (this.mt[i-1] >>> 30)
+    this.mt[i] = (this.mt[i] ^ (((((s & 0xffff0000) >>> 16) * 1664525) << 16) + ((s & 0x0000ffff) * 1664525)))
+      + init_key[j] + j; /* non linear */
+    this.mt[i] >>>= 0; /* for WORDSIZE > 32 machines */
+    i++; j++;
+    if (i>=this.N) { this.mt[0] = this.mt[this.N-1]; i=1; }
+    if (j>=key_length) j=0;
+  }
+  for (k=this.N-1; k; k--) {
+    var s = this.mt[i-1] ^ (this.mt[i-1] >>> 30);
+    this.mt[i] = (this.mt[i] ^ (((((s & 0xffff0000) >>> 16) * 1566083941) << 16) + (s & 0x0000ffff) * 1566083941))
+      - i; /* non linear */
+    this.mt[i] >>>= 0; /* for WORDSIZE > 32 machines */
+    i++;
+    if (i>=this.N) { this.mt[0] = this.mt[this.N-1]; i=1; }
+  }
+
+  this.mt[0] = 0x80000000; /* MSB is 1; assuring non-zero initial array */ 
+}
+ 
+/* generates a random number on [0,0xffffffff]-interval */
+MersenneTwister.prototype.genrand_int32 = function() {
+  var y;
+  var mag01 = new Array(0x0, this.MATRIX_A);
+  /* mag01[x] = x * MATRIX_A  for x=0,1 */
+
+  if (this.mti >= this.N) { /* generate N words at one time */
+    var kk;
+
+    if (this.mti == this.N+1)   /* if init_genrand() has not been called, */
+      this.init_genrand(5489); /* a default initial seed is used */
+
+    for (kk=0;kk<this.N-this.M;kk++) {
+      y = (this.mt[kk]&this.UPPER_MASK)|(this.mt[kk+1]&this.LOWER_MASK);
+      this.mt[kk] = this.mt[kk+this.M] ^ (y >>> 1) ^ mag01[y & 0x1];
+    }
+    for (;kk<this.N-1;kk++) {
+      y = (this.mt[kk]&this.UPPER_MASK)|(this.mt[kk+1]&this.LOWER_MASK);
+      this.mt[kk] = this.mt[kk+(this.M-this.N)] ^ (y >>> 1) ^ mag01[y & 0x1];
+    }
+    y = (this.mt[this.N-1]&this.UPPER_MASK)|(this.mt[0]&this.LOWER_MASK);
+    this.mt[this.N-1] = this.mt[this.M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
+
+    this.mti = 0;
+  }
+
+  y = this.mt[this.mti++];
+
+  /* Tempering */
+  y ^= (y >>> 11);
+  y ^= (y << 7) & 0x9d2c5680;
+  y ^= (y << 15) & 0xefc60000;
+  y ^= (y >>> 18);
+
+  return y >>> 0;
+}
+ 
+/* generates a random number on [0,0x7fffffff]-interval */
+MersenneTwister.prototype.genrand_int31 = function() {
+  return (this.genrand_int32()>>>1);
+}
+ 
+/* generates a random number on [0,1]-real-interval */
+MersenneTwister.prototype.genrand_real1 = function() {
+  return this.genrand_int32()*(1.0/4294967295.0); 
+  /* divided by 2^32-1 */ 
+}
+
+/* generates a random number on [0,1)-real-interval */
+MersenneTwister.prototype.random = function() {
+  return this.genrand_int32()*(1.0/4294967296.0); 
+  /* divided by 2^32 */
+}
+ 
+/* generates a random number on (0,1)-real-interval */
+MersenneTwister.prototype.genrand_real3 = function() {
+  return (this.genrand_int32() + 0.5)*(1.0/4294967296.0); 
+  /* divided by 2^32 */
+}
+ 
+/* generates a random number on [0,1) with 53-bit resolution*/
+MersenneTwister.prototype.genrand_res53 = function() { 
+  var a=this.genrand_int32()>>>5, b=this.genrand_int32()>>>6; 
+  return(a*67108864.0+b)*(1.0/9007199254740992.0); 
+} 
+
+/* These real versions are due to Isaku Wada, 2002/01/09 added */
+if(typeof exports == 'undefined'){
+  var root = this;
+} else {
+  var root = exports;
+}
+root.MersenneTwister = MersenneTwister;
--- a/common/lib/xmodule/xmodule/tests/test_files/js/test_problem_display.coffee
+++ b/common/lib/xmodule/xmodule/tests/test_files/js/test_problem_display.coffee
@@ -0,0 +1,21 @@
+class MinimaxProblemDisplay extends XProblemDisplay
+
+  constructor: (@state, @submission, @evaluation, @container, @submissionField, @parameters={}) ->
+
+    super(@state, @submission, @evaluation, @container, @submissionField, @parameters)
+
+  render: () ->
+
+  createSubmission: () ->
+
+    @newSubmission = {}
+
+    if @submission?
+      for id, value of @submission
+        @newSubmission[id] = value
+
+  getCurrentSubmission: () ->
+    return @newSubmission
+
+root = exports ? this
+root.TestProblemDisplay = TestProblemDisplay
--- a/common/lib/xmodule/xmodule/tests/test_files/js/test_problem_display.js
+++ b/common/lib/xmodule/xmodule/tests/test_files/js/test_problem_display.js
@@ -0,0 +1,49 @@
+// Generated by CoffeeScript 1.3.3
+(function() {
+  var MinimaxProblemDisplay, root,
+    __hasProp = {}.hasOwnProperty,
+    __extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; };
+
+  MinimaxProblemDisplay = (function(_super) {
+
+    __extends(MinimaxProblemDisplay, _super);
+
+    function MinimaxProblemDisplay(state, submission, evaluation, container, submissionField, parameters) {
+      this.state = state;
+      this.submission = submission;
+      this.evaluation = evaluation;
+      this.container = container;
+      this.submissionField = submissionField;
+      this.parameters = parameters != null ? parameters : {};
+      MinimaxProblemDisplay.__super__.constructor.call(this, this.state, this.submission, this.evaluation, this.container, this.submissionField, this.parameters);
+    }
+
+    MinimaxProblemDisplay.prototype.render = function() {};
+
+    MinimaxProblemDisplay.prototype.createSubmission = function() {
+      var id, value, _ref, _results;
+      this.newSubmission = {};
+      if (this.submission != null) {
+        _ref = this.submission;
+        _results = [];
+        for (id in _ref) {
+          value = _ref[id];
+          _results.push(this.newSubmission[id] = value);
+        }
+        return _results;
+      }
+    };
+
+    MinimaxProblemDisplay.prototype.getCurrentSubmission = function() {
+      return this.newSubmission;
+    };
+
+    return MinimaxProblemDisplay;
+
+  })(XProblemDisplay);
+
+  root = typeof exports !== "undefined" && exports !== null ? exports : this;
+
+  root.TestProblemDisplay = TestProblemDisplay;
+
+}).call(this);
--- a/common/lib/xmodule/xmodule/tests/test_files/js/test_problem_generator.coffee
+++ b/common/lib/xmodule/xmodule/tests/test_files/js/test_problem_generator.coffee
@@ -0,0 +1,14 @@
+class TestProblemGenerator extends XProblemGenerator
+
+  constructor: (seed, @parameters = {}) ->
+
+    super(seed, @parameters)
+
+  generate: () ->
+
+    @problemState.value = @parameters.value
+
+    return @problemState
+
+root = exports ? this
+root.generatorClass = TestProblemGenerator
--- a/common/lib/xmodule/xmodule/tests/test_files/js/test_problem_generator.js
+++ b/common/lib/xmodule/xmodule/tests/test_files/js/test_problem_generator.js
@@ -0,0 +1,29 @@
+// Generated by CoffeeScript 1.3.3
+(function() {
+  var TestProblemGenerator, root,
+    __hasProp = {}.hasOwnProperty,
+    __extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; };
+
+  TestProblemGenerator = (function(_super) {
+
+    __extends(TestProblemGenerator, _super);
+
+    function TestProblemGenerator(seed, parameters) {
+      this.parameters = parameters != null ? parameters : {};
+      TestProblemGenerator.__super__.constructor.call(this, seed, this.parameters);
+    }
+
+    TestProblemGenerator.prototype.generate = function() {
+      this.problemState.value = this.parameters.value;
+      return this.problemState;
+    };
+
+    return TestProblemGenerator;
+
+  })(XProblemGenerator);
+
+  root = typeof exports !== "undefined" && exports !== null ? exports : this;
+
+  root.generatorClass = TestProblemGenerator;
+
+}).call(this);
--- a/common/lib/xmodule/xmodule/tests/test_files/js/test_problem_grader.coffee
+++ b/common/lib/xmodule/xmodule/tests/test_files/js/test_problem_grader.coffee
@@ -0,0 +1,27 @@
+class TestProblemGrader extends XProblemGrader
+
+  constructor: (@submission, @problemState, @parameters={}) ->
+
+    super(@submission, @problemState, @parameters)
+
+  solve: () ->
+
+    @solution = {0: @problemState.value}
+
+  grade: () ->
+
+    if not @solution?
+      @solve()
+
+    allCorrect = true
+
+    for id, value of @solution
+      valueCorrect = if @submission? then (value == @submission[id]) else false
+      @evaluation[id] = valueCorrect
+      if not valueCorrect
+        allCorrect = false
+
+    return allCorrect
+
+root = exports ? this
+root.graderClass = TestProblemGrader
--- a/common/lib/xmodule/xmodule/tests/test_files/js/test_problem_grader.js
+++ b/common/lib/xmodule/xmodule/tests/test_files/js/test_problem_grader.js
@@ -0,0 +1,50 @@
+// Generated by CoffeeScript 1.3.3
+(function() {
+  var TestProblemGrader, root,
+    __hasProp = {}.hasOwnProperty,
+    __extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; };
+
+  TestProblemGrader = (function(_super) {
+
+    __extends(TestProblemGrader, _super);
+
+    function TestProblemGrader(submission, problemState, parameters) {
+      this.submission = submission;
+      this.problemState = problemState;
+      this.parameters = parameters != null ? parameters : {};
+      TestProblemGrader.__super__.constructor.call(this, this.submission, this.problemState, this.parameters);
+    }
+
+    TestProblemGrader.prototype.solve = function() {
+      return this.solution = {
+        0: this.problemState.value
+      };
+    };
+
+    TestProblemGrader.prototype.grade = function() {
+      var allCorrect, id, value, valueCorrect, _ref;
+      if (!(this.solution != null)) {
+        this.solve();
+      }
+      allCorrect = true;
+      _ref = this.solution;
+      for (id in _ref) {
+        value = _ref[id];
+        valueCorrect = this.submission != null ? value === this.submission[id] : false;
+        this.evaluation[id] = valueCorrect;
+        if (!valueCorrect) {
+          allCorrect = false;
+        }
+      }
+      return allCorrect;
+    };
+
+    return TestProblemGrader;
+
+  })(XProblemGrader);
+
+  root = typeof exports !== "undefined" && exports !== null ? exports : this;
+
+  root.graderClass = TestProblemGrader;
+
+}).call(this);
--- a/common/lib/xmodule/xmodule/tests/test_files/js/xproblem.coffee
+++ b/common/lib/xmodule/xmodule/tests/test_files/js/xproblem.coffee
@@ -0,0 +1,47 @@
+class XProblemGenerator
+  
+  constructor: (seed, @parameters={}) ->
+
+    @random = new MersenneTwister(seed)
+
+    @problemState = {}
+
+  generate: () ->
+
+    console.error("Abstract method called: XProblemGenerator.generate")
+
+class XProblemDisplay
+
+  constructor: (@state, @submission, @evaluation, @container, @submissionField, @parameters={}) ->
+
+  render: () ->
+
+    console.error("Abstract method called: XProblemDisplay.render")
+
+  updateSubmission: () ->
+
+    @submissionField.val(JSON.stringify(@getCurrentSubmission()))
+
+  getCurrentSubmission: () ->
+    console.error("Abstract method called: XProblemDisplay.getCurrentSubmission")
+
+class XProblemGrader
+
+  constructor: (@submission, @problemState, @parameters={}) ->
+
+    @solution   = null
+    @evaluation = {}
+
+  solve: () ->
+
+    console.error("Abstract method called: XProblemGrader.solve")
+
+  grade: () ->
+
+    console.error("Abstract method called: XProblemGrader.grade")
+
+root = exports ? this
+
+root.XProblemGenerator = XProblemGenerator
+root.XProblemDisplay   = XProblemDisplay
+root.XProblemGrader    = XProblemGrader
--- a/common/lib/xmodule/xmodule/tests/test_files/js/xproblem.js
+++ b/common/lib/xmodule/xmodule/tests/test_files/js/xproblem.js
@@ -0,0 +1,78 @@
+// Generated by CoffeeScript 1.3.3
+(function() {
+  var XProblemDisplay, XProblemGenerator, XProblemGrader, root;
+
+  XProblemGenerator = (function() {
+
+    function XProblemGenerator(seed, parameters) {
+      this.parameters = parameters != null ? parameters : {};
+      this.random = new MersenneTwister(seed);
+      this.problemState = {};
+    }
+
+    XProblemGenerator.prototype.generate = function() {
+      return console.error("Abstract method called: XProblemGenerator.generate");
+    };
+
+    return XProblemGenerator;
+
+  })();
+
+  XProblemDisplay = (function() {
+
+    function XProblemDisplay(state, submission, evaluation, container, submissionField, parameters) {
+      this.state = state;
+      this.submission = submission;
+      this.evaluation = evaluation;
+      this.container = container;
+      this.submissionField = submissionField;
+      this.parameters = parameters != null ? parameters : {};
+    }
+
+    XProblemDisplay.prototype.render = function() {
+      return console.error("Abstract method called: XProblemDisplay.render");
+    };
+
+    XProblemDisplay.prototype.updateSubmission = function() {
+      return this.submissionField.val(JSON.stringify(this.getCurrentSubmission()));
+    };
+
+    XProblemDisplay.prototype.getCurrentSubmission = function() {
+      return console.error("Abstract method called: XProblemDisplay.getCurrentSubmission");
+    };
+
+    return XProblemDisplay;
+
+  })();
+
+  XProblemGrader = (function() {
+
+    function XProblemGrader(submission, problemState, parameters) {
+      this.submission = submission;
+      this.problemState = problemState;
+      this.parameters = parameters != null ? parameters : {};
+      this.solution = null;
+      this.evaluation = {};
+    }
+
+    XProblemGrader.prototype.solve = function() {
+      return console.error("Abstract method called: XProblemGrader.solve");
+    };
+
+    XProblemGrader.prototype.grade = function() {
+      return console.error("Abstract method called: XProblemGrader.grade");
+    };
+
+    return XProblemGrader;
+
+  })();
+
+  root = typeof exports !== "undefined" && exports !== null ? exports : this;
+
+  root.XProblemGenerator = XProblemGenerator;
+
+  root.XProblemDisplay = XProblemDisplay;
+
+  root.XProblemGrader = XProblemGrader;
+
+}).call(this);
--- a/common/lib/xmodule/xmodule/x_module.py
+++ b/common/lib/xmodule/xmodule/x_module.py
@@ -675,7 +675,8 @@ class ModuleSystem(object):
                 filestore=None,
                 debug=False,
                 xqueue=None,
-                 is_staff=False):
+                 is_staff=False,
+                 node_path=""):
        '''
        Create a closure around the system environment.

@@ -718,6 +719,7 @@ class ModuleSystem(object):
        self.seed = user.id if user is not None else 0
        self.replace_urls = replace_urls
        self.is_staff = is_staff
+        self.node_path = node_path

    def get(self, attr):
        '''	provide uniform access to attributes (like etree).'''
--- a/common/static/coffee/src/xproblem.coffee
+++ b/common/static/coffee/src/xproblem.coffee
@@ -0,0 +1,47 @@
+class XProblemGenerator
+  
+  constructor: (seed, @parameters={}) ->
+
+    @random = new MersenneTwister(seed)
+
+    @problemState = {}
+
+  generate: () ->
+
+    console.error("Abstract method called: XProblemGenerator.generate")
+
+class XProblemDisplay
+
+  constructor: (@state, @submission, @evaluation, @container, @submissionField, @parameters={}) ->
+
+  render: () ->
+
+    console.error("Abstract method called: XProblemDisplay.render")
+
+  updateSubmission: () ->
+
+    @submissionField.val(JSON.stringify(@getCurrentSubmission()))
+
+  getCurrentSubmission: () ->
+    console.error("Abstract method called: XProblemDisplay.getCurrentSubmission")
+
+class XProblemGrader
+
+  constructor: (@submission, @problemState, @parameters={}) ->
+
+    @solution   = null
+    @evaluation = {}
+
+  solve: () ->
+
+    console.error("Abstract method called: XProblemGrader.solve")
+
+  grade: () ->
+
+    console.error("Abstract method called: XProblemGrader.grade")
+
+root = exports ? this
+
+root.XProblemGenerator = XProblemGenerator
+root.XProblemDisplay   = XProblemDisplay
+root.XProblemGrader    = XProblemGrader
--- a/common/static/js/vendor/mersenne-twister-min.js
+++ b/common/static/js/vendor/mersenne-twister-min.js
@@ -0,0 +1,202 @@
+/*
+  I've wrapped Makoto Matsumoto and Takuji Nishimura's code in a namespace
+  so it's better encapsulated. Now you can have multiple random number generators
+  and they won't stomp all over eachother's state.
+  
+  If you want to use this as a substitute for Math.random(), use the random()
+  method like so:
+  
+  var m = new MersenneTwister();
+  var randomNumber = m.random();
+  
+  You can also call the other genrand_{foo}() methods on the instance.
+
+  If you want to use a specific seed in order to get a repeatable random
+  sequence, pass an integer into the constructor:
+
+  var m = new MersenneTwister(123);
+
+  and that will always produce the same random sequence.
+
+  Sean McCullough (banksean@gmail.com)
+*/
+
+/* 
+   A C-program for MT19937, with initialization improved 2002/1/26.
+   Coded by Takuji Nishimura and Makoto Matsumoto.
+ 
+   Before using, initialize the state by using init_genrand(seed)  
+   or init_by_array(init_key, key_length).
+ 
+   Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
+   All rights reserved.                          
+ 
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+ 
+     1. Redistributions of source code must retain the above copyright
+        notice, this list of conditions and the following disclaimer.
+ 
+     2. Redistributions in binary form must reproduce the above copyright
+        notice, this list of conditions and the following disclaimer in the
+        documentation and/or other materials provided with the distribution.
+ 
+     3. The names of its contributors may not be used to endorse or promote 
+        products derived from this software without specific prior written 
+        permission.
+ 
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ 
+ 
+   Any feedback is very welcome.
+   http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
+   email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)
+*/
+
+var MersenneTwister = function(seed) {
+  if (seed == undefined) {
+    seed = new Date().getTime();
+  } 
+  /* Period parameters */  
+  this.N = 624;
+  this.M = 397;
+  this.MATRIX_A = 0x9908b0df;   /* constant vector a */
+  this.UPPER_MASK = 0x80000000; /* most significant w-r bits */
+  this.LOWER_MASK = 0x7fffffff; /* least significant r bits */
+ 
+  this.mt = new Array(this.N); /* the array for the state vector */
+  this.mti=this.N+1; /* mti==N+1 means mt[N] is not initialized */
+
+  this.init_genrand(seed);
+}  
+ 
+/* initializes mt[N] with a seed */
+MersenneTwister.prototype.init_genrand = function(s) {
+  this.mt[0] = s >>> 0;
+  for (this.mti=1; this.mti<this.N; this.mti++) {
+      var s = this.mt[this.mti-1] ^ (this.mt[this.mti-1] >>> 30);
+   this.mt[this.mti] = (((((s & 0xffff0000) >>> 16) * 1812433253) << 16) + (s & 0x0000ffff) * 1812433253)
+  + this.mti;
+      /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
+      /* In the previous versions, MSBs of the seed affect   */
+      /* only MSBs of the array mt[].                        */
+      /* 2002/01/09 modified by Makoto Matsumoto             */
+      this.mt[this.mti] >>>= 0;
+      /* for >32 bit machines */
+  }
+}
+ 
+/* initialize by an array with array-length */
+/* init_key is the array for initializing keys */
+/* key_length is its length */
+/* slight change for C++, 2004/2/26 */
+MersenneTwister.prototype.init_by_array = function(init_key, key_length) {
+  var i, j, k;
+  this.init_genrand(19650218);
+  i=1; j=0;
+  k = (this.N>key_length ? this.N : key_length);
+  for (; k; k--) {
+    var s = this.mt[i-1] ^ (this.mt[i-1] >>> 30)
+    this.mt[i] = (this.mt[i] ^ (((((s & 0xffff0000) >>> 16) * 1664525) << 16) + ((s & 0x0000ffff) * 1664525)))
+      + init_key[j] + j; /* non linear */
+    this.mt[i] >>>= 0; /* for WORDSIZE > 32 machines */
+    i++; j++;
+    if (i>=this.N) { this.mt[0] = this.mt[this.N-1]; i=1; }
+    if (j>=key_length) j=0;
+  }
+  for (k=this.N-1; k; k--) {
+    var s = this.mt[i-1] ^ (this.mt[i-1] >>> 30);
+    this.mt[i] = (this.mt[i] ^ (((((s & 0xffff0000) >>> 16) * 1566083941) << 16) + (s & 0x0000ffff) * 1566083941))
+      - i; /* non linear */
+    this.mt[i] >>>= 0; /* for WORDSIZE > 32 machines */
+    i++;
+    if (i>=this.N) { this.mt[0] = this.mt[this.N-1]; i=1; }
+  }
+
+  this.mt[0] = 0x80000000; /* MSB is 1; assuring non-zero initial array */ 
+}
+ 
+/* generates a random number on [0,0xffffffff]-interval */
+MersenneTwister.prototype.genrand_int32 = function() {
+  var y;
+  var mag01 = new Array(0x0, this.MATRIX_A);
+  /* mag01[x] = x * MATRIX_A  for x=0,1 */
+
+  if (this.mti >= this.N) { /* generate N words at one time */
+    var kk;
+
+    if (this.mti == this.N+1)   /* if init_genrand() has not been called, */
+      this.init_genrand(5489); /* a default initial seed is used */
+
+    for (kk=0;kk<this.N-this.M;kk++) {
+      y = (this.mt[kk]&this.UPPER_MASK)|(this.mt[kk+1]&this.LOWER_MASK);
+      this.mt[kk] = this.mt[kk+this.M] ^ (y >>> 1) ^ mag01[y & 0x1];
+    }
+    for (;kk<this.N-1;kk++) {
+      y = (this.mt[kk]&this.UPPER_MASK)|(this.mt[kk+1]&this.LOWER_MASK);
+      this.mt[kk] = this.mt[kk+(this.M-this.N)] ^ (y >>> 1) ^ mag01[y & 0x1];
+    }
+    y = (this.mt[this.N-1]&this.UPPER_MASK)|(this.mt[0]&this.LOWER_MASK);
+    this.mt[this.N-1] = this.mt[this.M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
+
+    this.mti = 0;
+  }
+
+  y = this.mt[this.mti++];
+
+  /* Tempering */
+  y ^= (y >>> 11);
+  y ^= (y << 7) & 0x9d2c5680;
+  y ^= (y << 15) & 0xefc60000;
+  y ^= (y >>> 18);
+
+  return y >>> 0;
+}
+ 
+/* generates a random number on [0,0x7fffffff]-interval */
+MersenneTwister.prototype.genrand_int31 = function() {
+  return (this.genrand_int32()>>>1);
+}
+ 
+/* generates a random number on [0,1]-real-interval */
+MersenneTwister.prototype.genrand_real1 = function() {
+  return this.genrand_int32()*(1.0/4294967295.0); 
+  /* divided by 2^32-1 */ 
+}
+
+/* generates a random number on [0,1)-real-interval */
+MersenneTwister.prototype.random = function() {
+  return this.genrand_int32()*(1.0/4294967296.0); 
+  /* divided by 2^32 */
+}
+ 
+/* generates a random number on (0,1)-real-interval */
+MersenneTwister.prototype.genrand_real3 = function() {
+  return (this.genrand_int32() + 0.5)*(1.0/4294967296.0); 
+  /* divided by 2^32 */
+}
+ 
+/* generates a random number on [0,1) with 53-bit resolution*/
+MersenneTwister.prototype.genrand_res53 = function() { 
+  var a=this.genrand_int32()>>>5, b=this.genrand_int32()>>>6; 
+  return(a*67108864.0+b)*(1.0/9007199254740992.0); 
+} 
+
+/* These real versions are due to Isaku Wada, 2002/01/09 added */
+if(typeof exports == 'undefined'){
+  var root = this;
+} else {
+  var root = exports;
+}
+root.MersenneTwister = MersenneTwister;
--- a/lms/djangoapps/courseware/module_render.py
+++ b/lms/djangoapps/courseware/module_render.py
@@ -196,6 +196,7 @@ def get_module(user, request, location, student_module_cache, position=None):
                          # by the replace_static_urls code below
                          replace_urls=replace_urls,
                          is_staff=has_staff_access_to_location(user, location),
+                          node_path=settings.NODE_PATH
                          )
    # pass position specified in URL to module through ModuleSystem
    system.set('position', position)
--- a/lms/envs/common.py
+++ b/lms/envs/common.py
@@ -89,6 +89,18 @@ sys.path.append(PROJECT_ROOT / 'lib')
 sys.path.append(COMMON_ROOT / 'djangoapps')
 sys.path.append(COMMON_ROOT / 'lib')

+# For Node.js
+
+system_node_path = os.environ.get("NODE_PATH", None)
+if system_node_path is None:
+    system_node_path = "/usr/local/lib/node_modules"
+
+node_paths = [COMMON_ROOT / "static/js/vendor", 
+              COMMON_ROOT / "static/coffee/src",
+              system_node_path
+              ]
+NODE_PATH = ':'.join(node_paths)
+                          
 ################################## MITXWEB #####################################
 # This is where we stick our compiled template files. Most of the app uses Mako
 # templates
@@ -337,7 +349,7 @@ PIPELINE_ALWAYS_RECOMPILE = ['sass/application.scss', 'sass/ie.scss', 'sass/cour
 courseware_only_js = [
    PROJECT_ROOT / 'static/coffee/src/' + pth + '.coffee'
    for pth
-    in ['courseware', 'histogram', 'navigation', 'time', ]
+    in ['courseware', 'histogram', 'navigation', 'time']
 ]
 courseware_only_js += [
    pth for pth
@@ -465,6 +477,7 @@ if os.path.isdir(DATA_DIR):
                    js_timestamp     = os.stat(js_dir / new_filename).st_mtime
                    if coffee_timestamp <= js_timestamp:
                        continue
+                os.system("rm %s" % (js_dir / new_filename))
                os.system("coffee -c %s" % (js_dir / filename))

 PIPELINE_COMPILERS = [
--- a/run_watch_data.py
+++ b/run_watch_data.py
@@ -17,7 +17,7 @@ from watchdog.events import LoggingEventHandler, FileSystemEventHandler
 # watch fewer or more extensions, you can change EXTENSIONS. To watch all
 # extensions, add "*" to EXTENSIONS.

-WATCH_DIRS = ["../data"]
+WATCH_DIRS = ["../data", "common/lib/xmodule/xmodule/js"]
 EXTENSIONS = ["*", "xml", "js", "css", "coffee", "scss", "html"]

 WATCH_DIRS = [os.path.abspath(os.path.normpath(dir)) for dir in WATCH_DIRS]