Fixed issue #980: incorrect LaTeX capturing and MathJax rendering

notebook/static/notebook/js/mathjaxutils.js

@@ -55,11 +55,9 @@ define([
     // Other minor modifications are also due to StackExchange and are used with
     // permission.
 
-    var inline = "$"; // the inline math delimiter
-
     // MATHSPLIT contains the pattern for math delimiters and special symbols
     // needed for searching for math in the text input.
-    var MATHSPLIT = /(\$\$?|\\(?:begin|end)\{[a-z]*\*?\}|\\[\\{}$]|[{}]|(?:\n\s*)+|@@\d+@@)/i;
+    var MATHSPLIT = /(\$\$?|\\(?:begin|end)\{[a-z]*\*?\}|\\[{}$]|[{}]|(?:\n\s*)+|@@\d+@@|\\\\(?:\(|\)|\[|\]))/i;
 
     //  The math is in blocks i through j, so
     //    collect it into one block and clear the others.
@@ -173,11 +171,16 @@ define([
                 //  Look for math start delimiters and when
                 //    found, set up the end delimiter.
                 //
-                if (block === inline || block === "$$") {
+                if (block === "$" || block === "$$") {
                     start = i;
                     end = block;
                     braces = 0;
                 }
+                else if (block === "\\\\\(" || block === "\\\\\[") {
+                    start = i;
+                    end = block.slice(-1) === "(" ? "\\\\\)" : "\\\\\]";
+                    braces = 0;
+                }
                 else if (block.substr(1, 5) === "begin") {
                     start = i;
                     end = "\\end" + block.substr(6);
@@ -199,9 +202,27 @@ define([
     //    and clear the math array (no need to keep it around).
     //
     var replace_math = function (text, math) {
-        text = text.replace(/@@(\d+)@@/g, function (match, n) {
-            return math[n];
-        });
+    	//
+    	//  Replaces a math placeholder with its corresponding group.
+    	//  The math delimiters "\\(", "\\[", "\\)" and "\\]" are replaced
+    	//  removing one backslash in order to be interpreted correctly by MathJax.
+    	//
+        var math_group_process = function (match, n) {
+            var math_group = math[n];
+
+            if (math_group.substr(0, 3) === "\\\\\("  && math_group.substr(math_group.length - 3) === "\\\\\)") {
+                math_group = "\\\(" + math_group.substring(3, math_group.length - 3) + "\\\)";
+            } else if (math_group.substr(0, 3) === "\\\\\[" && math_group.substr(math_group.length - 3) === "\\\\\]") {
+                math_group = "\\\[" + math_group.substring(3, math_group.length - 3) + "\\\]";
+            }
+
+            return math_group;
+        };
+
+        // Replace all the math group placeholders in the text
+        // with the saved strings.
+        text = text.replace(/@@(\d+)@@/g, math_group_process);
+
         return text;
     };
 

notebook/tests/notebook/markdown.js

@@ -102,4 +102,55 @@ casper.notebook_test(function () {
     codeblock = '```aaaa\nx = 1\n```'
     result = '<pre><code class="cm-s-ipython language-aaaa">x = 1\n</code></pre>'
     md_render_test(codeblock, result, 'Markdown code block unknown language');
+
+    function mathjax_render_test(input_string, result, message){
+      casper.thenEvaluate(function (text){
+        window._test_result = null;
+        require(['notebook/js/mathjaxutils'],function(mathjaxutils){
+          window._test_result = mathjaxutils.remove_math(text);
+        });
+      }, {text: input_string});
+      casper.waitFor(function() {
+        return casper.evaluate(function(){
+          return window._test_result!==null;
+        });
+      });
+      casper.then(function(){
+        var return_val = casper.evaluate(function(){
+          var blah = window._test_result;
+          delete window._test_result;
+          return blah;
+        });
+        this.test.assertEquals(return_val[0], result[0], message+" markdown");
+        this.test.assertEquals(return_val[1].length, result[1].length, message+" math instance count");
+        for(var i=0; i<return_val[1].length; i++){
+          this.test.assertEquals(return_val[1][i], result[1][i], message+" math instance "+i);
+        };
+      });
+    };
+    var input_string_1 = 'x \\\\(a_{0}+ b_{T}\\\\) y \\\\(a_{0}+  b_{T}\\\\) z';
+    var expected_result_1 = ['x @@0@@ y @@1@@ z', ['\\\\(a_{0}+ b_{T}\\\\)','\\\\(a_{0}+  b_{T}\\\\)']];
+    var message_1 = "multiple inline(LaTeX style) with underscores";
+
+    var input_string_2 = 'x \\\\[a_{0}+ b_{T}\\\\] y \\\\[a_{0}+  b_{T}\\\\] z';
+    var expected_result_2 = ['x @@0@@ y @@1@@ z', ['\\\\[a_{0}+ b_{T}\\\\]','\\\\[a_{0}+  b_{T}\\\\]']];
+    var message_2 = "multiple equation (LaTeX style) with underscores";
+
+    var input_string_3 = 'x $a_{0}+ b_{T}$ y $a_{0}+  b_{T}$ z';
+    var expected_result_3 = ['x @@0@@ y @@1@@ z',['$a_{0}+ b_{T}$','$a_{0}+  b_{T}$']];
+    var message_3 = "multiple inline(TeX style) with underscores";
+
+    var input_string_4 = 'x $$a_{0}+ b_{T}$$ y $$a_{0}+  b_{T}$$ z';
+    var expected_result_4 = ['x @@0@@ y @@1@@ z', ['$$a_{0}+ b_{T}$$','$$a_{0}+  b_{T}$$']];
+    var message_4 = "multiple equation(TeX style) with underscores";
+
+    var input_string_5 = 'x \\begin{equation}a_{0}+ b_{T}\\end{equation} y \\begin{equation}a_{0}+  b_{T}\\end{equation} z';
+    var expected_result_5 = ['x @@0@@ y @@1@@ z',['\\begin{equation}a_{0}+ b_{T}\\end{equation}','\\begin{equation}a_{0}+  b_{T}\\end{equation}']];
+    var message_5 = "multiple equations with underscores";
+
+    mathjax_render_test(input_string_1, expected_result_1, message_1);
+    mathjax_render_test(input_string_2, expected_result_2, message_2);
+    mathjax_render_test(input_string_3, expected_result_3, message_3);
+    mathjax_render_test(input_string_4, expected_result_4, message_4);
+    mathjax_render_test(input_string_5, expected_result_5, message_5);
 });