highlighting while skipping code and mathjax (ugly and slow solution)

lms/static/coffee/src/customwmd.coffee

@@ -112,14 +112,16 @@ $ ->
 
   if Markdown?
     
-    Markdown.getMathCompatibleConverter = ->
+    Markdown.getMathCompatibleConverter = (postProcessor) ->
+      postProcessor ||= ((text) -> text)
       converter = Markdown.getSanitizingConverter()
       processor = new MathJaxProcessor()
       converter.hooks.chain "preConversion", MathJaxProcessor.removeMathWrapper(processor)
-      converter.hooks.chain "postConversion", MathJaxProcessor.replaceMathWrapper(processor)
+      converter.hooks.chain "postConversion", (text) ->
+        postProcessor(MathJaxProcessor.replaceMathWrapper(processor)(text))
       converter
 
-    Markdown.makeWmdEditor = (elem, appended_id, imageUploadUrl) ->
+    Markdown.makeWmdEditor = (elem, appended_id, imageUploadUrl, postProcessor) ->
       $elem = $(elem)
 
       if not $elem.length
@@ -136,7 +138,7 @@ $ ->
                    .append($("<div>").attr("id", "wmd-preview#{_append}").addClass("wmd-panel wmd-preview"))
         $elem.append($wmdPanel)
 
-      converter = Markdown.getMathCompatibleConverter()
+      converter = Markdown.getMathCompatibleConverter(postProcessor)
 
       ajaxFileUpload = (imageUploadUrl, input, startUploadHandler) ->
         $("#loading").ajaxStart(-> $(this).show()).ajaxComplete(-> $(this).hide())

lms/static/coffee/src/discussion/content.coffee

@@ -283,8 +283,13 @@ initializeFollowThread = (thread) ->
       text.replace(/\&lt\;highlight\&gt\;/g, "<span class='search-highlight'>")
           .replace(/\&lt\;\/highlight\&gt\;/g, "</span>")
 
+    stripHighlight = (text, type) ->
+      text.replace(/\&(amp\;)?lt\;highlight\&(amp\;)?gt\;/g, "")
+          .replace(/\&(amp\;)?lt\;\/highlight\&(amp\;)?gt\;/g, "")
+
+
     stripLatexHighlight = (text) ->
-      text
+      Discussion.processEachMathAndCode text, stripHighlight
 
     markdownWithHighlight = (text) ->
       converter = Markdown.getMathCompatibleConverter()
@@ -303,10 +308,7 @@ initializeFollowThread = (thread) ->
 
     $contentBody = $local(".content-body")
 
-    console.log "raw html:"
-    console.log $contentBody.html()
-    
-    $contentBody.html markdownWithHighlight $contentBody.html()
+    $contentBody.html Discussion.postMathJaxProcessor markdownWithHighlight $contentBody.html()
 
     MathJax.Hub.Queue ["Typeset", MathJax.Hub, $contentBody.attr("id")]
     id = $content.attr("_id")

lms/static/coffee/src/discussion/utils.coffee

@@ -95,12 +95,25 @@ wmdEditors = {}
       else
         success(response, textStatus, xhr)
 
+  postMathJaxProcessor: (text) ->
+    RE_INLINEMATH = /^\$([^\$]*)\$/g
+    RE_DISPLAYMATH = /^\$\$([^\$]*)\$\$/g
+    Discussion.processEachMathAndCode text, (s, type) ->
+      if type == 'display'
+        s.replace RE_DISPLAYMATH, ($0, $1) ->
+          "\\[" + $1 + "\\]"
+      else if type == 'inline'
+        s.replace RE_INLINEMATH, ($0, $1) ->
+          "\\(" + $1 + "\\)"
+      else
+        s
+
   makeWmdEditor: ($content, $local, cls_identifier) ->
     elem = $local(".#{cls_identifier}")
     id = $content.attr("_id")
     appended_id = "-#{cls_identifier}-#{id}"
     imageUploadUrl = Discussion.urlFor('upload')
-    editor = Markdown.makeWmdEditor elem, appended_id, imageUploadUrl
+    editor = Markdown.makeWmdEditor elem, appended_id, imageUploadUrl, Discussion.postMathJaxProcessor
     wmdEditors["#{cls_identifier}-#{id}"] = editor
     editor
 
@@ -164,3 +177,54 @@ wmdEditors = {}
         unfollowLink()
     else
       followLink()
+    
+  processEachMathAndCode: (text, processor) ->
+  
+    codeArchive = []
+
+    RE_DISPLAYMATH = /^([^\$]*?)\$\$([^\$].+?)\$\$(.*)$/m
+    RE_INLINEMATH = /^([^\$]*?)\$([^\$]+?)\$(.*)$/m
+
+    ESCAPED_DOLLAR = '@@ESCAPED_D@@'
+    ESCAPED_BACKSLASH = '@@ESCAPED_B@@'
+
+    processedText = ""
+
+    $div = $("<div>").html(text)
+
+    $div.find("code").each (index, code) ->
+      codeArchive.push $(code).html()
+      $(code).html(codeArchive.length - 1)
+
+    text = $div.html()
+    text = text.replace /\\\$/g, ESCAPED_DOLLAR
+
+    while true
+      if RE_INLINEMATH.test(text)
+        text = text.replace RE_INLINEMATH, ($0, $1, $2, $3) ->
+          processedText += $1 + processor("$" + $2 + "$", 'inline')
+          $3
+      else if RE_DISPLAYMATH.test(text)
+        text = text.replace RE_DISPLAYMATH, ($0, $1, $2, $3) ->
+          processedText += $1 + processor("$$" + $2 + "$$", 'display')
+          $3
+      else
+        processedText += text
+        break
+
+    text = processedText
+    text = text.replace(new RegExp(ESCAPED_DOLLAR), '\\$')
+
+    text = text.replace /\\\\\\\\/g, ESCAPED_BACKSLASH
+    text = text.replace /\\begin\{([a-z]*\*?)\}([\s\S]*?)\\end\{\1\}/img, ($0, $1, $2) ->
+      processor("\\begin{#{$1}}" + $2 + "\\end{#{$1}}")
+    text = text.replace(new RegExp(ESCAPED_BACKSLASH), '\\\\\\\\')
+
+    $div = $("<div>").html(text)
+    cnt = 0
+    $div.find("code").each (index, code) ->
+      $(code).html(processor(codeArchive[cnt], 'code'))
+      cnt += 1
+
+    $div.html()
+