use more explicit delimiters for latex equations in r markdown documents

src/cpp/core/markdown/Markdown.cpp

@@ -205,51 +205,72 @@ class MathFilter : boost::noncopyable
    MathFilter(std::string* pInput, std::string* pHTMLOutput)
       : pHTMLOutput_(pHTMLOutput)
    {
-      filter(boost::regex("\\${2}[\\s\\S]+?\\${2}"), pInput);
-      filter(boost::regex("\\$(?!\\s)[^$]*[^$\\s]\\$"), pInput);
+      filter(boost::regex("\\${2}latex(\\s[\\s\\S]+?)\\${2}"),
+                          pInput,
+                          &displayMathBlocks_);
+
+      filter(boost::regex("\\$latex(\\s[\\s\\S]+?)\\$"),
+                          pInput,
+                          &inlineMathBlocks_);
    }
 
    ~MathFilter()
    {
       try
       {
-         std::for_each(mathBlocks_.begin(),
-                       mathBlocks_.end(),
-                       boost::bind(&MathFilter::restore, this, _1));
+         std::for_each(
+            displayMathBlocks_.begin(),
+            displayMathBlocks_.end(),
+            boost::bind(&MathFilter::restore, this, _1, "\\[", "\\]"));
+
+         std::for_each(
+            inlineMathBlocks_.begin(),
+            inlineMathBlocks_.end(),
+            boost::bind(&MathFilter::restore, this, _1, "\\(", "\\)"));
       }
       catch(...)
       {
       }
    }
 
 private:
-   void filter(const boost::regex& re, std::string* pInput)
+   void filter(const boost::regex& re,
+               std::string* pInput,
+               std::map<std::string,std::string>* pMathBlocks)
    {
       // explicit function type required because the Formatter functor
       // supports 3 distinct signatures
       boost::function<std::string(
           boost::match_results<std::string::const_iterator>)> formatter =
-                                 boost::bind(&MathFilter::substitute, this, _1);
+                                 boost::bind(&MathFilter::substitute,
+                                             this, _1, pMathBlocks);
 
       *pInput = boost::regex_replace(*pInput, re, formatter);
    }
 
    std::string substitute(
-               boost::match_results<std::string::const_iterator> match)
+               boost::match_results<std::string::const_iterator> match,
+               std::map<std::string,std::string>* pMathBlocks)
    {
       std::string guid = core::system::generateUuid(false);
-      mathBlocks_.insert(std::make_pair(guid, match[0]));
+      pMathBlocks->insert(std::make_pair(guid, match[1]));
       return guid;
    }
 
-   void restore(const std::map<std::string,std::string>::value_type& block)
+   void restore(const std::map<std::string,std::string>::value_type& block,
+                const std::string& beginDelim,
+                const std::string& endDelim)
    {
-      boost::algorithm::replace_all(*pHTMLOutput_, block.first, block.second);
+      boost::algorithm::replace_first(
+                          *pHTMLOutput_,
+                          block.first,
+                          beginDelim + " " + block.second + " " + endDelim);
    }
 
 private:
    std::string* pHTMLOutput_;
-   std::map<std::string,std::string> mathBlocks_;
+   std::map<std::string,std::string> displayMathBlocks_;
+   std::map<std::string,std::string> inlineMathBlocks_;
 };
 
 } // anonymous namespace

src/cpp/session/modules/SessionHTMLPreview.cpp

@@ -565,11 +565,11 @@ bool requiresHighlighting(const std::string& htmlOutput)
 
 bool requiresMathjax(const std::string& htmlOutput)
 {
-   boost::regex inlineMathRegex("\\$(?!\\s)[^$]*[^$\\s]\\$");
+   boost::regex inlineMathRegex("\\\\\\(([\\s\\S]+?)\\\\\\)");
    if (boost::regex_search(htmlOutput, inlineMathRegex))
       return true;
 
-   boost::regex displayMathRegex("\\${2}[\\s\\S]+?\\${2}");
+   boost::regex displayMathRegex("\\\\\\[([\\s\\S]+?)\\\\\\]");
    if (boost::regex_search(htmlOutput, displayMathRegex))
       return true;
 
@@ -639,12 +639,16 @@ void modifyOutputForPreview(std::string* pOutput)
                 "config=TeX-AMS-MML_SVG");
 #else
       // add HTML-CSS options required for correct qtwebkit rendering
-      std::string target = "tex2jax: {";
+      std::string target = "<!-- MathJax scripts -->";
       boost::algorithm::replace_first(
                *pOutput,
                target,
-               "\"HTML-CSS\": { minScaleAdjust: 125, availableFonts: [] }, "
-               + target);
+               target + "\n"
+               "<script type=\"text/x-mathjax-config\">"
+                  "MathJax.Hub.Config({"
+                  "  \"HTML-CSS\": { minScaleAdjust: 125, availableFonts: [] } "
+                  " });"
+               "</script>");
 #endif
 
       // serve mathjax locally

src/cpp/session/resources/markdown_help.html

@@ -133,9 +133,9 @@ <h4>Inline Code</h4>
 
 <h4>LaTeX Equations</h4>
 <p>Inline and display LaTeX equations:</p>
-<pre><code>$<i>equation</i>$
+<pre><code>$latex <i>equation</i> $
 
-$$
+$$latex
   <i>equation</i>
 $$
 </code></pre>

src/cpp/session/resources/mathjax.html

@@ -1,13 +1,4 @@
-<script type="text/x-mathjax-config">
-   MathJax.Hub.Config({
-      tex2jax: {
-         processEscapes: true,
-         processEnvironments: false,
-         inlineMath: [ ['$','$'] ],
-         displayMath: [ ['$$','$$'] ]
-      }
-    });
-</script>
+<!-- MathJax scripts -->
 <script type="text/javascript" src="https://c328740.ssl.cf1.rackcdn.com/mathjax/2.0-latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML">
 </script>
 

src/gwt/acesupport/acemode/markdown_highlight_rules.js

@@ -80,11 +80,12 @@ var MarkdownHighlightRules = function() {
             regex : "^[ ]{0,2}(?:[ ]?\\_[ ]?){3,}\\s*$"
         }, { // MathJax $$
             token : "markup.list",
-            regex : "\\${2}",
-            next  : "mathjax"
+            regex : "\\${2}latex\\s",
+            next  : "mathjaxdisplay"
         }, { // MathJax $
-            token : ["markup.list","support.function","markup.list"],
-              regex : "(\\$)" + "((?!\\s)[^$]*[^$\\s])" + "(\\$)"
+            token : "markup.list",
+            regex : "\\$latex\\s",
+            next  : "mathjaxinline"
         }, { // list
             token : "text",
             regex : "^\\s{0,3}(?:[*+-]|\\d+\\.)\\s+",
@@ -134,13 +135,22 @@ var MarkdownHighlightRules = function() {
             regex : ".+"
         } ],
 
-        "mathjax" : [ {
+        "mathjaxdisplay" : [ {
             token : "markup.list",
             regex : "\\${2}",
             next  : "start"
         }, {
             token : "support.function",
             regex : "[^\\$]+"
+        } ],
+
+        "mathjaxinline" : [ {
+            token : "markup.list",
+            regex : "\\$",
+            next  : "start"
+        }, {
+            token : "support.function",
+            regex : "[^\\$]+"
         } ]
     };
 };