Implement odd matching rules for emphasis

lib/rules_inline/balance_pairs.js

@@ -23,12 +23,20 @@ module.exports = function link_pairs(state) {
           currDelim.end < 0 &&
           currDelim.level === lastDelim.level) {
 
+        // typeofs are for backward compatibility with plugins
+        var odd_match = (currDelim.close || lastDelim.open) &&
+                        typeof currDelim.length !== 'undefined' &&
+                        typeof lastDelim.length !== 'undefined' &&
+                        (currDelim.length + lastDelim.length) % 3 === 0;
+
+        if (!odd_match) {
           lastDelim.jump = i - j;
           lastDelim.open = false;
           currDelim.end  = i;
           currDelim.jump = 0;
           break;
         }
+      }
 
       j -= currDelim.jump + 1;
     }

lib/rules_inline/emphasis.js

@@ -25,6 +25,10 @@ module.exports.tokenize = function emphasis(state, silent) {
       //
       marker: marker,
 
+      // Total length of these series of delimiters.
+      //
+      length: scanned.length,
+
       // An amount of characters before this one that's equivalent to
       // current one. In plain English: if this delimiter does not open
       // an emphasis, neither do previous `jump` characters.

test/fixtures/commonmark/bad.txt

@@ -242,59 +242,3 @@ error:
 </ul>
 
 
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 6546
-
-.
-*foo**bar**baz*
-.
-<p><em>foo<strong>bar</strong>baz</em></p>
-.
-
-error:
-
-<p><em>foo</em><em>bar</em><em>baz</em></p>
-
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 6585
-
-.
-*foo**bar***
-.
-<p><em>foo<strong>bar</strong></em></p>
-.
-
-error:
-
-<p><em>foo</em><em>bar</em>**</p>
-
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 6592
-
-.
-*foo**bar***
-.
-<p><em>foo<strong>bar</strong></em></p>
-.
-
-error:
-
-<p><em>foo</em><em>bar</em>**</p>
-
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 6690
-
-.
-**foo*bar*baz**
-.
-<p><strong>foo<em>bar</em>baz</strong></p>
-.
-
-error:
-
-<p><em><em>foo</em>bar</em>baz**</p>
-
-

test/fixtures/commonmark/good.txt

@@ -5001,6 +5001,15 @@ src line: 6540
 <p><em>foo <strong>bar</strong> baz</em></p>
 .
 
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+src line: 6546
+
+.
+*foo**bar**baz*
+.
+<p><em>foo<strong>bar</strong>baz</em></p>
+.
+
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 src line: 6571
 
@@ -5019,6 +5028,24 @@ src line: 6578
 <p><em>foo <strong>bar</strong></em></p>
 .
 
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+src line: 6585
+
+.
+*foo**bar***
+.
+<p><em>foo<strong>bar</strong></em></p>
+.
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+src line: 6592
+
+.
+*foo**bar***
+.
+<p><em>foo<strong>bar</strong></em></p>
+.
+
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 src line: 6600
 
@@ -5120,6 +5147,15 @@ src line: 6683
 <p><strong>foo <em>bar</em> baz</strong></p>
 .
 
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+src line: 6690
+
+.
+**foo*bar*baz**
+.
+<p><strong>foo<em>bar</em>baz</strong></p>
+.
+
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 src line: 6697