Merge branch 'emphstack'

Conflicts:
	Makefile
	js/lib/inlines.js

12 files changed, 2100 insertions, 487 deletions

diff --git a/Makefile b/Makefile
index 4a01824..e8a37d7 100644
--- a/Makefile
+++ b/Makefile
@@ -38,6 +38,9 @@ js/stmd.js: js/lib/index.js ${JSMODULES}
 testjs: spec.txt
 	node js/test.js
 
+jshint:
+	jshint ${JSMODULES}
+
 benchjs:
 	node js/bench.js ${BENCHINP}
 
@@ -57,14 +60,13 @@ $(SRCDIR)/case_fold_switch.inc: $(DATADIR)/CaseFolding-3.2.0.txt
 $(SRCDIR)/html/html_unescape.h: $(SRCDIR)/html/html_unescape.gperf
 	gperf -I -t -N find_entity -H hash_entity -K entity -C -l --null-strings -m5 $< > $@
 
-.PHONY: leakcheck clean fuzztest dingus upload
+.PHONY: leakcheck clean fuzztest dingus upload jshint test testjs benchjs
 
 dingus: js/stmd.js
 	cd js && echo "Starting dingus server at http://localhost:9000" && python -m SimpleHTTPServer 9000
 
 leakcheck: $(PROG)
-	# TODO produce leaktest.md that tests everything
-	cat leaktest.md | valgrind --leak-check=full --dsymutil=yes $(PROG)
+	cat leakcheck.md | valgrind --leak-check=full --dsymutil=yes $(PROG)
 
 operf: $(PROG)
 	operf $(PROG) <bench.md >/dev/null
diff --git a/TODO b/TODO
index 8b13789..be547e8 100644
--- a/TODO
+++ b/TODO
@@ -1 +1,8 @@
+- leakcheck reveals leak in new stmd code
+  Create a function to remove and free a stack entry
+  Use a while loop to remove and free all stack entries from top to the
+  one we're matching.
 
+- use name other than subj->last_emphasis
+
+- in js: make a proper stack (linked list) rather than using an array?
diff --git a/js/lib/inlines.js b/js/lib/inlines.js
index 34f1560..5fde099 100644
--- a/js/lib/inlines.js
+++ b/js/lib/inlines.js
@@ -262,93 +262,81 @@ var Str = function(s) {
 // Attempt to parse emphasis or strong emphasis.
 var parseEmphasis = function(cc,inlines) {
     var startpos = this.pos;
-    var c ;
-    var first_close = 0;
-    c = fromCodePoint(cc);
 
-    var numdelims;
-    var numclosedelims;
-    var delimpos;
-
-    // Get opening delimiters.
-    res = this.scanDelims(cc);
-    numdelims = res.numdelims;
+    var res = this.scanDelims(cc);
+    var numdelims = res.numdelims;
 
     if (numdelims === 0) {
         this.pos = startpos;
         return false;
     }
 
-    if (numdelims >= 4 || !res.can_open) {
-        this.pos += numdelims;
-        inlines.push(Str(this.subject.slice(startpos, startpos + numdelims)));
-        return true;
-    }
+    if (res.can_close) {
 
-    this.pos += numdelims;
+      // Walk the stack and find a matching opener, if possible
+      var opener = this.emphasis_openers;
+      while (opener) {
 
-    var delims_to_match = numdelims;
-
-    var current = [];
-    var firstend;
-    var firstpos;
-    var state = 0;
-    var can_close = false;
-    var can_open = false;
-    var last_emphasis_closer = null;
-    while (this.last_emphasis_closer[c] >= this.pos) {
-        res = this.scanDelims(cc);
-        numclosedelims = res.numdelims;
-
-        if (res.can_close) {
-            if (last_emphasis_closer === null ||
-                last_emphasis_closer < this.pos) {
-                last_emphasis_closer = this.pos;
-            }
-            if (numclosedelims === 3 && delims_to_match === 3) {
-                delims_to_match -= 3;
-                this.pos += 3;
-                current = [{t: 'Strong', c: [{t: 'Emph', c: current}]}];
-            } else if (numclosedelims >= 2 && delims_to_match >= 2) {
-                delims_to_match -= 2;
-                this.pos += 2;
-                firstend = current.length;
-                firstpos = this.pos;
-                current = [{t: 'Strong', c: current}];
-            } else if (numclosedelims >= 1 && delims_to_match >= 1) {
-                delims_to_match -= 1;
-                this.pos += 1;
-                firstend = current.length;
-                firstpos = this.pos;
-                current = [{t: 'Emph', c: current}];
-            } else {
-                if (!(this.parseInline(current,true))) {
-                    break;
-                }
-            }
-            if (delims_to_match === 0) {
-                Array.prototype.push.apply(inlines, current);
-                return true;
+        if (opener.cc === cc) { // we have a match!
+
+          if (opener.numdelims <= numdelims) { // all openers used
+
+            this.pos += opener.numdelims;
+            var X;
+            switch (opener.numdelims) {
+            case 3:
+                X = function(x) { return Strong([Emph(x)]); };
+                break;
+            case 2:
+                X = Strong;
+                break;
+            case 1:
+            default:
+                X = Emph;
+                break;
             }
-        } else if (!(this.parseInline(current,true))) {
-            break;
+            inlines[opener.pos] = X(inlines.slice(opener.pos + 1));
+            inlines.splice(opener.pos + 1, inlines.length - (opener.pos + 1));
+            // Remove entries after this, to prevent overlapping nesting:
+            this.emphasis_openers = opener.previous;
+            return true;
+
+          } else if (opener.numdelims > numdelims) { // only some openers used
+
+            this.pos += numdelims;
+            opener.numdelims -= numdelims;
+            inlines[opener.pos].c =
+              inlines[opener.pos].c.slice(0, opener.numdelims);
+            var X = numdelims === 2 ? Strong : Emph;
+            inlines[opener.pos + 1] = X(inlines.slice(opener.pos + 1));
+            inlines.splice(opener.pos + 2, inlines.length - (opener.pos + 2));
+            // Remove entries after this, to prevent overlapping nesting:
+            this.emphasis_openers = opener;
+            return true;
+
+          }
+
         }
+        opener = opener.previous;
+      }
     }
 
-    // we didn't match emphasis: fallback
-    inlines.push(Str(this.subject.slice(startpos,
-                                        startpos + delims_to_match)));
-    if (delims_to_match < numdelims) {
-        Array.prototype.push.apply(inlines, current.slice(0,firstend));
-        this.pos = firstpos;
-    } else { // delims_to_match === numdelims
-        this.pos = startpos + delims_to_match;
-    }
+    // If we're here, we didn't match a closer.
+
+    this.pos += numdelims;
+    inlines.push(Str(this.subject.slice(startpos, startpos + numdelims)));
+
+    if (res.can_open) {
 
-    if (last_emphasis_closer) {
-        this.last_emphasis_closer[c] = last_emphasis_closer;
+      // Add entry to stack for this opener
+      this.emphasis_openers = { cc: cc,
+                                numdelims: numdelims,
+                                pos: inlines.length - 1,
+                                previous: this.emphasis_openers };
     }
+
     return true;
+
 };
 
 // Attempt to parse link title (sans quotes), returning the string
@@ -629,18 +617,11 @@ var parseReference = function(s, refmap) {
 };
 
 // Parse the next inline element in subject, advancing subject position.
-// If memoize is set, memoize the result.
 // On success, add the result to the inlines list, and return true.
 // On failure, return false.
-var parseInline = function(inlines, memoize) {
+var parseInline = function(inlines) {
     var startpos = this.pos;
     var origlen = inlines.length;
-    var memoized = memoize && this.memo[startpos];
-    if (memoized) {
-        this.pos = memoized.endpos;
-        Array.prototype.push.apply(inlines, memoized.inline);
-        return true;
-    }
 
     var c = this.peek();
     if (c === -1) {
@@ -683,10 +664,6 @@ var parseInline = function(inlines, memoize) {
         inlines.push({t: 'Str', c: fromCodePoint(c)});
     }
 
-    if (memoize) {
-        this.memo[startpos] = { inline: inlines.slice(origlen),
-                                endpos: this.pos };
-    }
     return true;
 };
 
@@ -695,10 +672,9 @@ var parseInlines = function(s, refmap) {
     this.subject = s;
     this.pos = 0;
     this.refmap = refmap || {};
-    this.memo = {};
-    this.last_emphasis_closer = { '*': s.length, '_': s.length };
+    this.emphasis_openers = null;
     var inlines = [];
-    while (this.parseInline(inlines, false)) {
+    while (this.parseInline(inlines)) {
     }
     return inlines;
 };
@@ -708,10 +684,9 @@ function InlineParser(){
     return {
         subject: '',
         label_nest_level: 0, // used by parseLinkLabel method
-        last_emphasis_closer: null,  // used by parseEmphasis method
+        emphasis_openers: null,  // used by parseEmphasis method
         pos: 0,
         refmap: {},
-        memo: {},
         match: match,
         peek: peek,
         spnl: spnl,
diff --git a/leakcheck.md b/leakcheck.md
new file mode 100644
index 0000000..06716e1
--- /dev/null
+++ b/leakcheck.md
@@ -0,0 +1,1561 @@
+→foo→baz→→bim
+
+    a→a
+    ὐ→a
+
+- `one
+- two`
+
+***
+---
+___
+
++++
+
+===
+
+--
+**
+__
+
+ ***
+  ***
+   ***
+
+    ***
+
+Foo
+    ***
+
+_____________________________________
+
+ - - -
+
+ **  * ** * ** * **
+
+-     -      -      -
+
+- - - -    
+
+_ _ _ _ a
+
+a------
+
+ *-*
+
+- foo
+***
+- bar
+
+Foo
+***
+bar
+
+Foo
+---
+bar
+
+* Foo
+* * *
+* Bar
+
+- Foo
+- * * *
+
+# foo
+## foo
+### foo
+#### foo
+##### foo
+###### foo
+
+####### foo
+
+#5 bolt
+
+\## foo
+
+# foo *bar* \*baz\*
+
+#                  foo                     
+
+ ### foo
+  ## foo
+   # foo
+
+    # foo
+
+foo
+    # bar
+
+## foo ##
+  ###   bar    ###
+
+# foo ##################################
+##### foo ##
+
+### foo ###     
+
+### foo ### b
+
+### foo \###
+## foo \#\##
+# foo \#
+
+****
+## foo
+****
+
+Foo bar
+# baz
+Bar foo
+
+## 
+#
+### ###
+
+Foo *bar*
+=========
+
+Foo *bar*
+---------
+
+Foo
+-------------------------
+
+Foo
+=
+
+   Foo
+---
+
+  Foo
+-----
+
+  Foo
+  ===
+
+    Foo
+    ---
+
+    Foo
+---
+
+Foo
+   ----      
+
+Foo
+     ---
+
+Foo
+= =
+
+Foo
+--- -
+
+Foo  
+-----
+
+Foo\
+----
+
+`Foo
+----
+`
+
+<a title="a lot
+---
+of dashes"/>
+
+> Foo
+---
+
+Foo
+Bar
+---
+
+Foo
+Bar
+===
+
+---
+Foo
+---
+Bar
+---
+Baz
+
+
+====
+
+    a simple
+      indented code block
+
+    <a/>
+    *hi*
+
+    - one
+
+    chunk1
+
+    chunk2
+  
+ 
+ 
+    chunk3
+
+    chunk1
+      
+      chunk2
+
+Foo
+    bar
+
+
+    foo
+bar
+
+# Header
+    foo
+Header
+------
+    foo
+----
+
+        foo
+    bar
+
+
+    
+    foo
+    
+
+
+    foo  
+
+```
+<
+ >
+```
+
+~~~
+<
+ >
+~~~
+
+```
+aaa
+~~~
+```
+
+~~~
+aaa
+```
+~~~
+
+````
+aaa
+```
+``````
+
+~~~~
+aaa
+~~~
+~~~~
+
+```
+
+`````
+
+```
+aaa
+
+```
+
+  
+```
+
+```
+```
+
+ ```
+ aaa
+aaa
+```
+
+  ```
+aaa
+  aaa
+aaa
+  ```
+
+   ```
+   aaa
+    aaa
+  aaa
+   ```
+
+    ```
+    aaa
+    ```
+
+``` ```
+aaa
+
+~~~~~~
+aaa
+~~~ ~~
+
+foo
+```
+bar
+```
+baz
+
+foo
+---
+~~~
+bar
+~~~
+# baz
+
+```ruby
+def foo(x)
+  return 3
+end
+```
+
+~~~~    ruby startline=3 $%@#$
+def foo(x)
+  return 3
+end
+~~~~~~~
+
+````;
+````
+
+``` aa ```
+foo
+
+```
+``` aaa
+```
+
+<table>
+  <tr>
+    <td>
+           hi
+    </td>
+  </tr>
+</table>
+
+okay.
+
+ <div>
+  *hello*
+         <foo><a>
+
+<DIV CLASS="foo">
+
+*Markdown*
+
+</DIV>
+
+<div></div>
+``` c
+int x = 33;
+```
+
+<!-- Foo
+bar
+   baz -->
+
+<?php
+  echo 'foo'
+?>
+
+<![CDATA[
+function matchwo(a,b)
+{
+if (a < b && a < 0) then
+  {
+  return 1;
+  }
+else
+  {
+  return 0;
+  }
+}
+]]>
+
+  <!-- foo -->
+
+    <!-- foo -->
+
+Foo
+<div>
+bar
+</div>
+
+<div>
+bar
+</div>
+*foo*
+
+<div class
+foo
+
+<div>
+
+*Emphasized* text.
+
+</div>
+
+<div>
+*Emphasized* text.
+</div>
+
+<table>
+
+<tr>
+
+<td>
+Hi
+</td>
+
+</tr>
+
+</table>
+
+[foo]: /url "title"
+
+[foo]
+
+   [foo]: 
+      /url  
+           'the title'  
+
+[foo]
+
+[Foo*bar\]]:my_(url) 'title (with parens)'
+
+[Foo*bar\]]
+
+[Foo bar]:
+<my url>
+'title'
+
+[Foo bar]
+
+[foo]:
+/url
+
+[foo]
+
+[foo]:
+
+[foo]
+
+[foo]
+
+[foo]: url
+
+[foo]
+
+[foo]: first
+[foo]: second
+
+[FOO]: /url
+
+[Foo]
+
+[ΑΓΩ]: /φου
+
+[αγω]
+
+[foo]: /url
+
+[foo]: /url "title" ok
+
+    [foo]: /url "title"
+
+[foo]
+
+```
+[foo]: /url
+```
+
+[foo]
+
+Foo
+[bar]: /baz
+
+[bar]
+
+# [Foo]
+[foo]: /url
+> bar
+
+[foo]: /foo-url "foo"
+[bar]: /bar-url
+  "bar"
+[baz]: /baz-url
+
+[foo],
+[bar],
+[baz]
+
+[foo]
+
+> [foo]: /url
+
+aaa
+
+bbb
+
+aaa
+bbb
+
+ccc
+ddd
+
+aaa
+
+
+bbb
+
+  aaa
+ bbb
+
+aaa
+             bbb
+                                       ccc
+
+   aaa
+bbb
+
+    aaa
+bbb
+
+aaa     
+bbb     
+
+  
+
+aaa
+  
+
+# aaa
+
+  
+
+> # Foo
+> bar
+> baz
+
+># Foo
+>bar
+> baz
+
+   > # Foo
+   > bar
+ > baz
+
+    > # Foo
+    > bar
+    > baz
+
+> # Foo
+> bar
+baz
+
+> bar
+baz
+> foo
+
+> foo
+---
+
+> - foo
+- bar
+
+>     foo
+    bar
+
+> ```
+foo
+```
+
+>
+
+>
+>  
+> 
+
+>
+> foo
+>  
+
+> foo
+
+> bar
+
+> foo
+> bar
+
+> foo
+>
+> bar
+
+foo
+> bar
+
+> aaa
+***
+> bbb
+
+> bar
+baz
+
+> bar
+
+baz
+
+> bar
+>
+baz
+
+> > > foo
+bar
+
+>>> foo
+> bar
+>>baz
+
+>     code
+
+>    not code
+
+A paragraph
+with two lines.
+
+    indented code
+
+> A block quote.
+
+1.  A paragraph
+    with two lines.
+
+        indented code
+
+    > A block quote.
+
+- one
+
+ two
+
+- one
+
+  two
+
+ -    one
+
+     two
+
+ -    one
+
+      two
+
+   > > 1.  one
+>>
+>>     two
+
+>>- one
+>>
+  >  > two
+
+- foo
+
+  bar
+
+- foo
+
+
+  bar
+
+- ```
+  foo
+
+
+  bar
+  ```
+
+1.  foo
+
+    ```
+    bar
+    ```
+
+    baz
+
+    > bam
+
+- foo
+
+      bar
+
+  10.  foo
+
+           bar
+
+    indented code
+
+paragraph
+
+    more code
+
+1.     indented code
+
+   paragraph
+
+       more code
+
+1.      indented code
+
+   paragraph
+
+       more code
+
+   foo
+
+bar
+
+-    foo
+
+  bar
+
+-  foo
+
+   bar
+
+ 1.  A paragraph
+     with two lines.
+
+         indented code
+
+     > A block quote.
+
+  1.  A paragraph
+      with two lines.
+
+          indented code
+
+      > A block quote.
+
+   1.  A paragraph
+       with two lines.
+
+           indented code
+
+       > A block quote.
+
+    1.  A paragraph
+        with two lines.
+
+            indented code
+
+        > A block quote.
+
+  1.  A paragraph
+with two lines.
+
+          indented code
+
+      > A block quote.
+
+  1.  A paragraph
+    with two lines.
+
+> 1. > Blockquote
+continued here.
+
+> 1. > Blockquote
+> continued here.
+
+- foo
+  - bar
+    - baz
+
+- foo
+ - bar
+  - baz
+
+10) foo
+    - bar
+
+10) foo
+   - bar
+
+- - foo
+
+1. - 2. foo
+
+- foo
+-
+- bar
+
+-
+
+- foo
+- bar
++ baz
+
+1. foo
+2. bar
+3) baz
+
+- foo
+
+- bar
+
+
+- baz
+
+- foo
+
+
+  bar
+- baz
+
+- foo
+  - bar
+    - baz
+
+
+      bim
+
+- foo
+- bar
+
+
+- baz
+- bim
+
+-   foo
+
+    notcode
+
+-   foo
+
+
+    code
+
+- a
+ - b
+  - c
+   - d
+  - e
+ - f
+- g
+
+- a
+- b
+
+- c
+
+* a
+*
+
+* c
+
+- a
+- b
+
+  c
+- d
+
+- a
+- b
+
+  [ref]: /url
+- d
+
+- a
+- ```
+  b
+
+
+  ```
+- c
+
+- a
+  - b
+
+    c
+- d
+
+* a
+  > b
+  >
+* c
+
+- a
+  > b
+  ```
+  c
+  ```
+- d
+
+- a
+
+- a
+  - b
+
+* foo
+  * bar
+
+  baz
+
+- a
+  - b
+  - c
+
+- d
+  - e
+  - f
+
+`hi`lo`
+
+\!\"\#\$\%\&\'\(\)\*\+\,\-\.\/\:\;\<\=\>\?\@\[\\\]\^\_\`\{\|\}\~
+
+\→\A\a\ \3\φ\«
+
+\*not emphasized*
+\<br/> not a tag
+\[not a link](/foo)
+\`not code`
+1\. not a list
+\* not a list
+\# not a header
+\[foo]: /url "not a reference"
+
+\\*emphasis*
+
+foo\
+bar
+
+`` \[\` ``
+
+    \[\]
+
+~~~
+\[\]
+~~~
+
+<http://example.com?find=\*>
+
+<a href="/bar\/)">
+
+[foo](/bar\* "ti\*tle")
+
+[foo]
+
+[foo]: /bar\* "ti\*tle"
+
+``` foo\+bar
+foo
+```
+
+&nbsp; &amp; &copy; &AElig; &Dcaron; &frac34; &HilbertSpace; &DifferentialD; &ClockwiseContourIntegral;
+
+&#35; &#1234; &#992; &#98765432;
+
+&#X22; &#XD06; &#xcab;
+
+&nbsp &x; &#; &#x; &ThisIsWayTooLongToBeAnEntityIsntIt; &hi?;
+
+&copy
+
+&MadeUpEntity;
+
+<a href="&ouml;&ouml;.html">
+
+[foo](/f&ouml;&ouml; "f&ouml;&ouml;")
+
+[foo]
+
+[foo]: /f&ouml;&ouml; "f&ouml;&ouml;"
+
+``` f&ouml;&ouml;
+foo
+```
+
+`f&ouml;&ouml;`
+
+    f&ouml;f&ouml;
+
+`foo`
+
+`` foo ` bar  ``
+
+` `` `
+
+``
+foo
+``
+
+`foo   bar
+  baz`
+
+`foo `` bar`
+
+`foo\`bar`
+
+*foo`*`
+
+[not a `link](/foo`)
+
+<http://foo.bar.`baz>`
+
+<a href="`">`
+
+```foo``
+
+`foo
+
+*foo bar*
+
+_foo bar_
+
+**foo bar**
+
+__foo bar__
+
+*foo
+bar*
+
+_foo
+bar_
+
+**foo
+bar**
+
+__foo
+bar__
+
+*foo [bar](/url)*
+
+_foo [bar](/url)_
+
+**foo [bar](/url)**
+
+__foo [bar](/url)__
+
+*foo [bar*](/url)
+
+_foo [bar_](/url)
+
+**<a href="**">
+
+__<a href="__">
+
+*a `*`*
+
+_a `_`_
+
+**a<http://foo.bar?q=**>
+
+__a<http://foo.bar?q=__>
+
+and * foo bar*
+
+_ foo bar_
+
+and ** foo bar**
+
+__ foo bar__
+
+and *foo bar *
+
+and _foo bar _
+
+and **foo bar **
+
+and __foo bar __
+
+****hi****
+
+_____hi_____
+
+Sign here: _________
+
+** is not an empty emphasis
+
+**** is not an empty strong emphasis
+
+*here is a \**
+
+__this is a double underscore (`__`)__
+
+*_*
+
+_*_
+
+*__*
+
+_**_
+
+foo*bar*baz
+
+foo_bar_baz
+
+foo__bar__baz
+
+_foo_bar_baz_
+
+11*15*32
+
+11_15_32
+
+_foo_bar_baz_
+
+__foo__bar__baz__
+
+***foo bar***
+
+___foo bar___
+
+***foo** bar*
+
+___foo__ bar_
+
+***foo* bar**
+
+___foo_ bar__
+
+*foo **bar***
+
+_foo __bar___
+
+**foo *bar***
+
+__foo _bar___
+
+*foo **bar***
+
+_foo __bar___
+
+*foo *bar* baz*
+
+_foo _bar_ baz_
+
+**foo **bar** baz**
+
+__foo __bar__ baz__
+
+*foo **bar** baz*
+
+_foo __bar__ baz_
+
+**foo *bar* baz**
+
+__foo _bar_ baz__
+
+**foo, *bar*, baz**
+
+__foo, _bar_, baz__
+
+*foo**bar**baz*
+
+**foo*bar*baz**
+
+**foo**
+
+****foo****
+
+*_foo_*
+
+**__foo__**
+
+*foo**
+
+*foo *bar**
+
+**foo***
+
+***foo* bar***
+
+***foo** bar***
+
+*foo**bar***
+
+*foo****
+
+*foo**
+
+**foo*
+
+*foo *bar**
+
+**foo* bar*
+
+*bar***
+
+***foo*
+
+**bar***
+
+***foo**
+
+***foo *bar*
+
+[link](/uri "title")
+
+[link](/uri)
+
+[link]()
+
+[link](<>)
+
+[link](/my uri)
+
+[link](</my uri>)
+
+[link](foo
+bar)
+
+[link]((foo)and(bar))
+
+[link](foo(and(bar)))
+
+[link](foo(and\(bar\)))
+
+[link](<foo(and(bar))>)
+
+[link](foo\)\:)
+
+[link](foo%20b&auml;)
+
+[link]("title")
+
+[link](/url "title")
+[link](/url 'title')
+[link](/url (title))
+
+[link](/url "title \"&quot;")
+
+[link](/url "title "and" title")
+
+[link](/url 'title "and" title')
+
+[link](   /uri
+  "title"  )
+
+[link] (/uri)
+
+[foo <bar attr="](baz)">
+
+[foo][bar]
+
+[bar]: /url "title"
+
+[*foo\!*][bar]
+
+[bar]: /url "title"
+
+[foo][BaR]
+
+[bar]: /url "title"
+
+[Толпой][Толпой] is a Russian word.
+
+[ТОЛПОЙ]: /url
+
+[Foo
+  bar]: /url
+
+[Baz][Foo bar]
+
+[foo] [bar]
+
+[bar]: /url "title"
+
+[foo]
+[bar]
+
+[bar]: /url "title"
+
+[foo]: /url1
+
+[foo]: /url2
+
+[bar][foo]
+
+[bar][foo\!]
+
+[foo!]: /url
+
+[foo][]
+
+[foo]: /url "title"
+
+[*foo* bar][]
+
+[*foo* bar]: /url "title"
+
+[Foo][]
+
+[foo]: /url "title"
+
+[foo] 
+[]
+
+[foo]: /url "title"
+
+[foo]
+
+[foo]: /url "title"
+
+[*foo* bar]
+
+[*foo* bar]: /url "title"
+
+[[*foo* bar]]
+
+[*foo* bar]: /url "title"
+
+[Foo]
+
+[foo]: /url "title"
+
+\[foo]
+
+[foo]: /url "title"
+
+[foo*]: /url
+
+*[foo*]
+
+[foo`]: /url
+
+[foo`]`
+
+[[[foo]]]
+
+[[[foo]]]: /url
+
+[[[foo]]]
+
+[[[foo]]]: /url1
+[foo]: /url2
+
+[\[foo]
+
+[\[foo]: /url
+
+[foo][bar]
+
+[foo]: /url1
+[bar]: /url2
+
+[foo][bar][baz]
+
+[baz]: /url
+
+[foo][bar][baz]
+
+[baz]: /url1
+[bar]: /url2
+
+[foo][bar][baz]
+
+[baz]: /url1
+[foo]: /url2
+
+![foo](/url "title")
+
+![foo *bar*]
+
+[foo *bar*]: train.jpg "train & tracks"
+
+![foo *bar*][]
+
+[foo *bar*]: train.jpg "train & tracks"
+
+![foo *bar*][foobar]
+
+[FOOBAR]: train.jpg "train & tracks"
+
+![foo](train.jpg)
+
+My ![foo bar](/path/to/train.jpg  "title"   )
+
+![foo](<url>)
+
+![](/url)
+
+![foo] [bar]
+
+[bar]: /url
+
+![foo] [bar]
+
+[BAR]: /url
+
+![foo][]
+
+[foo]: /url "title"
+
+![*foo* bar][]
+
+[*foo* bar]: /url "title"
+
+![Foo][]
+
+[foo]: /url "title"
+
+![foo] 
+[]
+
+[foo]: /url "title"
+
+![foo]
+
+[foo]: /url "title"
+
+![*foo* bar]
+
+[*foo* bar]: /url "title"
+
+![[foo]]
+
+[[foo]]: /url "title"
+
+![Foo]
+
+[foo]: /url "title"
+
+\!\[foo]
+
+[foo]: /url "title"
+
+\![foo]
+
+[foo]: /url "title"
+
+<http://foo.bar.baz>
+
+<http://foo.bar.baz?q=hello&id=22&boolean>
+
+<irc://foo.bar:2233/baz>
+
+<MAILTO:FOO@BAR.BAZ>
+
+<http://foo.bar/baz bim>
+
+<foo@bar.example.com>
+
+<foo+special@Bar.baz-bar0.com>
+
+<>
+
+<heck://bing.bong>
+
+< http://foo.bar >
+
+<foo.bar.baz>
+
+<localhost:5001/foo>
+
+http://example.com
+
+foo@bar.example.com
+
+<a><bab><c2c>
+
+<a/><b2/>
+
+<a  /><b2
+data="foo" >
+
+<a foo="bar" bam = 'baz <em>"</em>'
+_boolean zoop:33=zoop:33 />
+
+<33> <__>
+
+<a h*#ref="hi">
+
+<a href="hi'> <a href=hi'>
+
+< a><
+foo><bar/ >
+
+<a href='bar'title=title>
+
+</a>
+</foo >
+
+</a href="foo">
+
+foo <!-- this is a
+comment - with hyphen -->
+
+foo <!-- not a comment -- two hyphens -->
+
+foo <?php echo $a; ?>
+
+foo <!ELEMENT br EMPTY>
+
+foo <![CDATA[>&<]]>
+
+<a href="&ouml;">
+
+<a href="\*">
+
+<a href="\"">
+
+foo  
+baz
+
+foo\
+baz
+
+foo       
+baz
+
+foo  
+     bar
+
+foo\
+     bar
+
+*foo  
+bar*
+
+*foo\
+bar*
+
+`code  
+span`
+
+`code\
+span`
+
+<a href="foo  
+bar">
+
+<a href="foo\
+bar">
+
+foo
+baz
+
+foo 
+ baz
+
+hello $.;'there
+
+Foo χρῆν
+
+Multiple     spaces
+
diff --git a/spec.txt b/spec.txt
index 0c09c43..3f10459 100644
--- a/spec.txt
+++ b/spec.txt
@@ -4095,21 +4095,39 @@ for efficient parsing strategies that do not backtrack:
     (c) it is not followed by an ASCII alphanumeric character.
 
 9.  Emphasis begins with a delimiter that [can open
-    emphasis](#can-open-emphasis) and includes inlines parsed
-    sequentially until a delimiter that [can close
+    emphasis](#can-open-emphasis) and ends with a delimiter that [can close
     emphasis](#can-close-emphasis), and that uses the same
-    character (`_` or `*`) as the opening delimiter, is reached.
+    character (`_` or `*`) as the opening delimiter.  The inlines
+    between the open delimiter and the closing delimiter are the
+    contents of the emphasis inline.
 
 10. Strong emphasis begins with a delimiter that [can open strong
-    emphasis](#can-open-strong-emphasis) and includes inlines parsed
-    sequentially until a delimiter that [can close strong
-    emphasis](#can-close-strong-emphasis), and that uses the
-    same character (`_` or `*`) as the opening delimiter, is reached.
+    emphasis](#can-open-strong-emphasis) and ends with a delimiter that
+    [can close strong emphasis](#can-close-strong-emphasis), and that uses the
+    same character (`_` or `*`) as the opening delimiter.  The inlines
+    between the open delimiter and the closing delimiter are the
+    contents of the strong emphasis inline.
 
-11. In case of ambiguity, strong emphasis takes precedence.  Thus,
-    `**foo**` is `<strong>foo</strong>`, not `<em><em>foo</em></em>`,
-    and `***foo***` is `<strong><em>foo</em></strong>`, not
-    `<em><strong>foo</strong></em>` or `<em><em><em>foo</em></em></em>`.
+Where rules 1--10 above are compatible with multiple parsings,
+the following principles resolve ambiguity:
+
+11. An interpretation `<strong>...</strong>` is always preferred to
+    `<em><em>...</em></em>`.
+
+12. An interpretation `<strong><em>...</em></strong>` is always
+    preferred to `<em><strong>..</strong></em>`.
+
+13. When two potential emphasis or strong emphasis spans overlap,
+    the first takes precedence.  Thus, for example, `*foo _bar* baz_`
+    is parsed as `<em>foo _bar</em> baz_` rather than
+    `*foo <em>bar* baz</em>`.
+
+14. Inline code spans, links, images, and HTML tags group more tightly
+    than emphasis.  So, when there is a choice between an interpretation
+    that contains one of these elements and one that does not, the
+    former always wins.  Thus, for example, `*[foo*](bar)` is
+    parsed as `*<a href="bar">foo*</a>` rather than as
+    `<em>[foo</em>](bar)`.
 
 These rules can be illustrated through a series of examples.
 
@@ -4689,6 +4707,15 @@ We retain symmetry in these cases:
 <p><em><em>foo</em> bar</em></p>
 .
 
+Note that this is not a case of strong emphasis,
+since the interior `*` closes regular emphasis:
+
+.
+**foo bar* baz**
+.
+<p><em><em>foo bar</em> baz</em>*</p>
+.
+
 More cases with mismatched delimiters:
 
 .
@@ -4721,6 +4748,67 @@ More cases with mismatched delimiters:
 <p>***foo <em>bar</em></p>
 .
 
+The following case illustrates rule 13:
+
+.
+*foo _bar* baz_
+.
+<p><em>foo _bar</em> baz_</p>
+.
+
+The following cases illustrate rule 14:
+
+.
+*[foo*](bar)
+.
+<p>*<a href="bar">foo*</a></p>
+.
+
+.
+*![foo*](bar)
+.
+<p>*<img src="bar" alt="foo*" /></p>
+.
+
+.
+*<img src="foo" title="*"/>
+.
+<p>*<img src="foo" title="*"/></p>
+.
+
+.
+*a`a*`
+.
+<p>*a<code>a*</code></p>
+.
+
+Here is a tricky case that can be a performance problem with some
+parsers:
+
+.
+*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a
+.
+<p>*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a
+*a **a *a **a *a **a *a **a</p>
+.
+
 ## Links
 
 A link contains a [link label](#link-label) (the visible text),
diff --git a/src/blocks.c b/src/blocks.c
index 5b38116..c0c7e23 100644
--- a/src/blocks.c
+++ b/src/blocks.c
@@ -47,13 +47,13 @@ bool is_blank(strbuf *s, int offset)
 {
 	while (offset < s->size) {
 		switch (s->ptr[offset]) {
-			case '\n':
-				return true;
-			case ' ':
-				offset++;
-				break;
-			default:
-				return false;
+		case '\n':
+			return true;
+		case ' ':
+			offset++;
+			break;
+		default:
+			return false;
 		}
 	}
 
@@ -63,17 +63,17 @@ bool is_blank(strbuf *s, int offset)
 static inline bool can_contain(int parent_type, int child_type)
 {
 	return ( parent_type == BLOCK_DOCUMENT ||
-			parent_type == BLOCK_BQUOTE ||
-			parent_type == BLOCK_LIST_ITEM ||
-			(parent_type == BLOCK_LIST && child_type == BLOCK_LIST_ITEM) );
+		 parent_type == BLOCK_BQUOTE ||
+		 parent_type == BLOCK_LIST_ITEM ||
+		 (parent_type == BLOCK_LIST && child_type == BLOCK_LIST_ITEM) );
 }
 
 static inline bool accepts_lines(int block_type)
 {
 	return (block_type == BLOCK_PARAGRAPH ||
-			block_type == BLOCK_ATX_HEADER ||
-			block_type == BLOCK_INDENTED_CODE ||
-			block_type == BLOCK_FENCED_CODE);
+		block_type == BLOCK_ATX_HEADER ||
+		block_type == BLOCK_INDENTED_CODE ||
+		block_type == BLOCK_FENCED_CODE);
 }
 
 static void add_line(node_block* node_block, chunk *ch, int offset)
@@ -156,77 +156,77 @@ static void finalize(node_block* b, int line_number)
 	}
 
 	switch (b->tag) {
-		case BLOCK_PARAGRAPH:
-			pos = 0;
-			while (strbuf_at(&b->string_content, 0) == '[' &&
-					(pos = parse_reference_inline(&b->string_content, b->top->as.document.refmap))) {
-
-				strbuf_drop(&b->string_content, pos);
-			}
-			if (is_blank(&b->string_content, 0)) {
-				b->tag = BLOCK_REFERENCE_DEF;
-			}
-			break;
+	case BLOCK_PARAGRAPH:
+		pos = 0;
+		while (strbuf_at(&b->string_content, 0) == '[' &&
+		       (pos = parse_reference_inline(&b->string_content, b->top->as.document.refmap))) {
 
-		case BLOCK_INDENTED_CODE:
-			remove_trailing_blank_lines(&b->string_content);
-			strbuf_putc(&b->string_content, '\n');
-			break;
-
-		case BLOCK_FENCED_CODE:
-			// first line of contents becomes info
-			firstlinelen = strbuf_strchr(&b->string_content, '\n', 0);
-
-			strbuf_init(&b->as.code.info, 0);
-			houdini_unescape_html_f(
-				&b->as.code.info,
-				b->string_content.ptr,
-				firstlinelen
+			strbuf_drop(&b->string_content, pos);
+		}
+		if (is_blank(&b->string_content, 0)) {
+			b->tag = BLOCK_REFERENCE_DEF;
+		}
+		break;
+
+	case BLOCK_INDENTED_CODE:
+		remove_trailing_blank_lines(&b->string_content);
+		strbuf_putc(&b->string_content, '\n');
+		break;
+
+	case BLOCK_FENCED_CODE:
+		// first line of contents becomes info
+		firstlinelen = strbuf_strchr(&b->string_content, '\n', 0);
+
+		strbuf_init(&b->as.code.info, 0);
+		houdini_unescape_html_f(
+			&b->as.code.info,
+			b->string_content.ptr,
+			firstlinelen
 			);
 
-			strbuf_drop(&b->string_content, firstlinelen + 1);
+		strbuf_drop(&b->string_content, firstlinelen + 1);
 
-			strbuf_trim(&b->as.code.info);
-			strbuf_unescape(&b->as.code.info);
-			break;
+		strbuf_trim(&b->as.code.info);
+		strbuf_unescape(&b->as.code.info);
+		break;
 
-		case BLOCK_LIST: // determine tight/loose status
-			b->as.list.tight = true; // tight by default
-			item = b->children;
+	case BLOCK_LIST: // determine tight/loose status
+		b->as.list.tight = true; // tight by default
+		item = b->children;
 
-			while (item) {
-				// check for non-final non-empty list item ending with blank line:
-				if (item->last_line_blank && item->next) {
+		while (item) {
+			// check for non-final non-empty list item ending with blank line:
+			if (item->last_line_blank && item->next) {
+				b->as.list.tight = false;
+				break;
+			}
+			// recurse into children of list item, to see if there are
+			// spaces between them:
+			subitem = item->children;
+			while (subitem) {
+				if (ends_with_blank_line(subitem) &&
+				    (item->next || subitem->next)) {
 					b->as.list.tight = false;
 					break;
 				}
-				// recurse into children of list item, to see if there are
-				// spaces between them:
-				subitem = item->children;
-				while (subitem) {
-					if (ends_with_blank_line(subitem) &&
-							(item->next || subitem->next)) {
-						b->as.list.tight = false;
-						break;
-					}
-					subitem = subitem->next;
-				}
-				if (!(b->as.list.tight)) {
-					break;
-				}
-				item = item->next;
+				subitem = subitem->next;
 			}
+			if (!(b->as.list.tight)) {
+				break;
+			}
+			item = item->next;
+		}
 
-			break;
+		break;
 
-		default:
-			break;
+	default:
+		break;
 	}
 }
 
 // Add a node_block as child of another.  Return pointer to child.
 static node_block* add_child(node_block* parent,
-		int block_type, int start_line, int start_column)
+			     int block_type, int start_line, int start_column)
 {
 	assert(parent);
 
@@ -276,14 +276,14 @@ void stmd_free_nodes(node_block *e)
 void process_inlines(node_block* cur, reference_map *refmap)
 {
 	switch (cur->tag) {
-		case BLOCK_PARAGRAPH:
-		case BLOCK_ATX_HEADER:
-		case BLOCK_SETEXT_HEADER:
-			cur->inline_content = parse_inlines(&cur->string_content, refmap);
-			break;
-
-		default:
-			break;
+	case BLOCK_PARAGRAPH:
+	case BLOCK_ATX_HEADER:
+	case BLOCK_SETEXT_HEADER:
+		cur->inline_content = parse_inlines(&cur->string_content, refmap);
+		break;
+
+	default:
+		break;
 	}
 
 	node_block *child = cur->children;
@@ -355,9 +355,9 @@ static int parse_list_marker(chunk *input, int pos, struct ListData ** dataptr)
 static int lists_match(struct ListData *list_data, struct ListData *item_data)
 {
 	return (list_data->list_type == item_data->list_type &&
-			list_data->delimiter == item_data->delimiter &&
-			// list_data->marker_offset == item_data.marker_offset &&
-			list_data->bullet_char == item_data->bullet_char);
+		list_data->delimiter == item_data->delimiter &&
+		// list_data->marker_offset == item_data.marker_offset &&
+		list_data->bullet_char == item_data->bullet_char);
 }
 
 static node_block *finalize_document(node_block *document, int linenum)
@@ -486,7 +486,7 @@ static void incorporate_line(strbuf *line, int line_number, node_block** curptr)
 		} else if (container->tag == BLOCK_LIST_ITEM) {
 
 			if (indent >= container->as.list.marker_offset +
-					container->as.list.padding) {
+			    container->as.list.padding) {
 				offset += container->as.list.marker_offset +
 					container->as.list.padding;
 			} else if (blank) {
@@ -506,7 +506,7 @@ static void incorporate_line(strbuf *line, int line_number, node_block** curptr)
 			}
 
 		} else if (container->tag == BLOCK_ATX_HEADER ||
-				container->tag == BLOCK_SETEXT_HEADER) {
+			   container->tag == BLOCK_SETEXT_HEADER) {
 
 			// a header can never contain more than one line
 			all_matched = false;
@@ -550,7 +550,7 @@ static void incorporate_line(strbuf *line, int line_number, node_block** curptr)
 
 	// unless last matched container is code node_block, try new container starts:
 	while (container->tag != BLOCK_FENCED_CODE && container->tag != BLOCK_INDENTED_CODE &&
-			container->tag != BLOCK_HTML) {
+	       container->tag != BLOCK_HTML) {
 
 		first_nonspace = offset;
 		while (peek_at(&input, first_nonspace) == ' ')
@@ -603,17 +603,17 @@ static void incorporate_line(strbuf *line, int line_number, node_block** curptr)
 			// note, we don't adjust offset because the tag is part of the text
 
 		} else if (container->tag == BLOCK_PARAGRAPH &&
-				(lev = scan_setext_header_line(&input, first_nonspace)) &&
-				// check that there is only one line in the paragraph:
-				strbuf_strrchr(&container->string_content, '\n',
-					strbuf_len(&container->string_content) - 2) < 0) {
+			   (lev = scan_setext_header_line(&input, first_nonspace)) &&
+			   // check that there is only one line in the paragraph:
+			   strbuf_strrchr(&container->string_content, '\n',
+					  strbuf_len(&container->string_content) - 2) < 0) {
 
 			container->tag = BLOCK_SETEXT_HEADER;
 			container->as.header.level = lev;
 			offset = input.len - 1;
 
 		} else if (!(container->tag == BLOCK_PARAGRAPH && !all_matched) &&
-				(matched = scan_hrule(&input, first_nonspace))) {
+			   (matched = scan_hrule(&input, first_nonspace))) {
 
 			// it's only now that we know the line is not part of a setext header:
 			container = add_child(container, BLOCK_HRULE, line_number, first_nonspace + 1);
@@ -646,16 +646,16 @@ static void incorporate_line(strbuf *line, int line_number, node_block** curptr)
 			data->marker_offset = indent;
 
 			if (container->tag != BLOCK_LIST ||
-					!lists_match(&container->as.list, data)) {
+			    !lists_match(&container->as.list, data)) {
 				container = add_child(container, BLOCK_LIST, line_number,
-						first_nonspace + 1);
+						      first_nonspace + 1);
 
 				memcpy(&container->as.list, data, sizeof(*data));
 			}
 
 			// add the list item
 			container = add_child(container, BLOCK_LIST_ITEM, line_number,
-					first_nonspace + 1);
+					      first_nonspace + 1);
 			/* TODO: static */
 			memcpy(&container->as.list, data, sizeof(*data));
 			free(data);
@@ -684,11 +684,11 @@ static void incorporate_line(strbuf *line, int line_number, node_block** curptr)
 	// lists or breaking out of lists.  we also don't set last_line_blank
 	// on an empty list item.
 	container->last_line_blank = (blank &&
-			container->tag != BLOCK_BQUOTE &&
-			container->tag != BLOCK_FENCED_CODE &&
-			!(container->tag == BLOCK_LIST_ITEM &&
-				container->children == NULL &&
-				container->start_line == line_number));
+				      container->tag != BLOCK_BQUOTE &&
+				      container->tag != BLOCK_FENCED_CODE &&
+				      !(container->tag == BLOCK_LIST_ITEM &&
+					container->children == NULL &&
+					container->start_line == line_number));
 
 	node_block *cont = container;
 	while (cont->parent) {
@@ -697,10 +697,10 @@ static void incorporate_line(strbuf *line, int line_number, node_block** curptr)
 	}
 
 	if (cur != last_matched_container &&
-			container == last_matched_container &&
-			!blank &&
-			cur->tag == BLOCK_PARAGRAPH &&
-			strbuf_len(&cur->string_content) > 0) {
+	    container == last_matched_container &&
+	    !blank &&
+	    cur->tag == BLOCK_PARAGRAPH &&
+	    strbuf_len(&cur->string_content) > 0) {
 
 		add_line(cur, &input, offset);
 
@@ -721,7 +721,7 @@ static void incorporate_line(strbuf *line, int line_number, node_block** curptr)
 			matched = 0;
 
 			if (indent <= 3 &&
-				peek_at(&input, first_nonspace) == container->as.code.fence_char) {
+			    peek_at(&input, first_nonspace) == container->as.code.fence_char) {
 				int fence_len = scan_close_code_fence(&input, first_nonspace);
 				if (fence_len > container->as.code.fence_length)
 					matched = 1;
@@ -767,4 +767,3 @@ static void incorporate_line(strbuf *line, int line_number, node_block** curptr)
 		*curptr = container;
 	}
 }
-
diff --git a/src/buffer.c b/src/buffer.c
index 7c2b86b..2e32720 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -15,8 +15,8 @@
 unsigned char strbuf__initbuf[1];
 unsigned char strbuf__oom[1];
 
-#define ENSURE_SIZE(b, d) \
-	if ((d) > buf->asize && strbuf_grow(b, (d)) < 0)\
+#define ENSURE_SIZE(b, d)					\
+	if ((d) > buf->asize && strbuf_grow(b, (d)) < 0)	\
 		return -1;
 
 void strbuf_init(strbuf *buf, int initial_size)
@@ -111,8 +111,8 @@ int strbuf_set(strbuf *buf, const unsigned char *data, int len)
 int strbuf_sets(strbuf *buf, const char *string)
 {
 	return strbuf_set(buf,
-		(const unsigned char *)string,
-		string ? strlen(string) : 0);
+			  (const unsigned char *)string,
+			  string ? strlen(string) : 0);
 }
 
 int strbuf_putc(strbuf *buf, int c)
@@ -155,7 +155,7 @@ int strbuf_vprintf(strbuf *buf, const char *format, va_list ap)
 			(char *)buf->ptr + buf->size,
 			buf->asize - buf->size,
 			format, args
-		);
+			);
 
 		if (len < 0) {
 			free(buf->ptr);
@@ -351,4 +351,3 @@ extern void strbuf_unescape(strbuf *buf)
 
 	strbuf_truncate(buf, w);
 }
-
diff --git a/src/inlines.c b/src/inlines.c
index 71d75e9..07a75f9 100644
--- a/src/inlines.c
+++ b/src/inlines.c
@@ -10,11 +10,19 @@
 #include "scanners.h"
 #include "inlines.h"
 
+typedef struct InlineStack {
+	struct InlineStack *previous;
+	node_inl *first_inline;
+	int delim_count;
+	char delim_char;
+} inline_stack;
+
 typedef struct Subject {
 	chunk input;
 	int pos;
 	int label_nestlevel;
 	reference_map *refmap;
+	inline_stack *emphasis_openers;
 } subject;
 
 static node_inl *parse_chunk_inlines(chunk *chunk, reference_map *refmap);
@@ -108,26 +116,26 @@ extern void free_inlines(node_inl* e)
 	node_inl * next;
 	while (e != NULL) {
 		switch (e->tag){
-			case INL_STRING:
-			case INL_RAW_HTML:
-			case INL_CODE:
-				chunk_free(&e->content.literal);
-				break;
-			case INL_LINEBREAK:
-			case INL_SOFTBREAK:
-				break;
-			case INL_LINK:
-			case INL_IMAGE:
-				free(e->content.linkable.url);
-				free(e->content.linkable.title);
-				free_inlines(e->content.linkable.label);
-				break;
-			case INL_EMPH:
-			case INL_STRONG:
-				free_inlines(e->content.inlines);
-				break;
-			default:
-				break;
+		case INL_STRING:
+		case INL_RAW_HTML:
+		case INL_CODE:
+			chunk_free(&e->content.literal);
+			break;
+		case INL_LINEBREAK:
+		case INL_SOFTBREAK:
+			break;
+		case INL_LINK:
+		case INL_IMAGE:
+			free(e->content.linkable.url);
+			free(e->content.linkable.title);
+			free_inlines(e->content.linkable.label);
+			break;
+		case INL_EMPH:
+		case INL_STRONG:
+			free_inlines(e->content.inlines);
+			break;
+		default:
+			break;
 		}
 		next = e->next;
 		free(e);
@@ -158,6 +166,7 @@ static void subject_from_buf(subject *e, strbuf *buffer, reference_map *refmap)
 	e->pos = 0;
 	e->label_nestlevel = 0;
 	e->refmap = refmap;
+	e->emphasis_openers = NULL;
 
 	chunk_rtrim(&e->input);
 }
@@ -170,6 +179,7 @@ static void subject_from_chunk(subject *e, chunk *chunk, reference_map *refmap)
 	e->pos = 0;
 	e->label_nestlevel = 0;
 	e->refmap = refmap;
+	e->emphasis_openers = NULL;
 
 	chunk_rtrim(&e->input);
 }
@@ -262,12 +272,11 @@ static node_inl* handle_backticks(subject *subj)
 }
 
 // Scan ***, **, or * and return number scanned, or 0.
-// Don't advance position.
+// Advances position.
 static int scan_delims(subject* subj, char c, bool * can_open, bool * can_close)
 {
 	int numdelims = 0;
 	char char_before, char_after;
-	int startpos = subj->pos;
 
 	char_before = subj->pos == 0 ? '\n' : peek_at(subj, subj->pos - 1);
 	while (peek_char(subj) == c) {
@@ -281,135 +290,106 @@ static int scan_delims(subject* subj, char c, bool * can_open, bool * can_close)
 		*can_open = *can_open && !isalnum(char_before);
 		*can_close = *can_close && !isalnum(char_after);
 	}
-	subj->pos = startpos;
 	return numdelims;
 }
 
+static void free_openers(subject* subj, inline_stack* istack)
+{
+    inline_stack * tempstack;
+    while (subj->emphasis_openers != istack) {
+	tempstack = subj->emphasis_openers;
+	subj->emphasis_openers = subj->emphasis_openers->previous;
+	free(tempstack);
+    }
+}
+
 // Parse strong/emph or a fallback.
 // Assumes the subject has '_' or '*' at the current position.
-static node_inl* handle_strong_emph(subject* subj, char c)
+static node_inl* handle_strong_emph(subject* subj, char c, node_inl **last)
 {
 	bool can_open, can_close;
-	node_inl * result = NULL;
-	node_inl ** last = malloc(sizeof(node_inl *));
-	node_inl * new;
-	node_inl * il;
-	node_inl * first_head = NULL;
-	node_inl * first_close = NULL;
-	int first_close_delims = 0;
 	int numdelims;
-
-	*last = NULL;
+	int useDelims;
+	inline_stack * istack;
+	node_inl * inl;
+	node_inl * emph;
+	node_inl * inl_text;
 
 	numdelims = scan_delims(subj, c, &can_open, &can_close);
-	subj->pos += numdelims;
-
-	new = make_str(chunk_dup(&subj->input, subj->pos - numdelims, numdelims));
-	*last = new;
-	first_head = new;
-	result = new;
-
-	if (!can_open || numdelims == 0) {
-		goto done;
-	}
-
-	switch (numdelims) {
-		case 1:
-			while (true) {
-				numdelims = scan_delims(subj, c, &can_open, &can_close);
-				if (numdelims >= 1 && can_close) {
-					subj->pos += 1;
-					first_head->tag = INL_EMPH;
-					chunk_free(&first_head->content.literal);
-					first_head->content.inlines = first_head->next;
-					first_head->next = NULL;
-					goto done;
-				} else {
-					if (!parse_inline(subj, last)) {
-						goto done;
-					}
-				}
-			}
-			break;
-		case 2:
-			while (true) {
-				numdelims = scan_delims(subj, c, &can_open, &can_close);
-				if (numdelims >= 2 && can_close) {
-					subj->pos += 2;
-					first_head->tag = INL_STRONG;
-					chunk_free(&first_head->content.literal);
-					first_head->content.inlines = first_head->next;
-					first_head->next = NULL;
-					goto done;
-				} else {
-					if (!parse_inline(subj, last)) {
-						goto done;
-					}
-				}
-			}
-			break;
-		case 3:
-			while (true) {
-				numdelims = scan_delims(subj, c, &can_open, &can_close);
-				if (can_close && numdelims >= 1 && numdelims <= 3 &&
-						numdelims != first_close_delims) {
-					new = make_str(chunk_dup(&subj->input, subj->pos, numdelims));
-					append_inlines(*last, new);
-					*last = new;
-					if (first_close_delims == 1 && numdelims > 2) {
-						numdelims = 2;
-					} else if (first_close_delims == 2) {
-						numdelims = 1;
-					} else if (numdelims == 3) {
-						// If we opened with ***, we interpret it as ** followed by *
-						// giving us <strong><em>
-						numdelims = 1;
-					}
-					subj->pos += numdelims;
-					if (first_close) {
-						first_head->tag = first_close_delims == 1 ? INL_STRONG : INL_EMPH;
-						chunk_free(&first_head->content.literal);
-						first_head->content.inlines =
-							make_inlines(first_close_delims == 1 ? INL_EMPH : INL_STRONG,
-									first_head->next);
-
-						il = first_head->next;
-						while (il->next && il->next != first_close) {
-							il = il->next;
-						}
-						il->next = NULL;
-
-						first_head->content.inlines->next = first_close->next;
-
-						il = first_head->content.inlines;
-						while (il->next && il->next != *last) {
-							il = il->next;
-						}
-						il->next = NULL;
-						free_inlines(*last);
-
-						first_close->next = NULL;
-						free_inlines(first_close);
-						first_head->next = NULL;
-						goto done;
-					} else {
-						first_close = *last;
-						first_close_delims = numdelims;
-					}
-				} else {
-					if (!parse_inline(subj, last)) {
-						goto done;
-					}
-				}
-			}
-			break;
-		default:
-			goto done;
+
+	if (can_close)
+	{
+		// walk the stack and find a matching opener, if there is one
+		istack = subj->emphasis_openers;
+		while (true)
+		{
+			if (istack == NULL)
+				goto cannotClose;
+
+			if (istack->delim_char == c)
+				break;
+
+			istack = istack->previous;
+		}
+
+		// calculate the actual number of delimeters used from this closer
+		useDelims = istack->delim_count;
+		if (useDelims == 3) useDelims = numdelims == 3 ? 1 : numdelims;
+		else if (useDelims > numdelims) useDelims = 1;
+
+		if (istack->delim_count == useDelims)
+		{
+			// the opener is completely used up - remove the stack entry and reuse the inline element
+			inl = istack->first_inline;
+			inl->tag = useDelims == 1 ? INL_EMPH : INL_STRONG;
+			chunk_free(&inl->content.literal);
+			inl->content.inlines = inl->next;
+			inl->next = NULL;
+
+			// remove this opener and all later ones from stack:
+                        free_openers(subj, istack->previous);
+			*last = inl;
+		}
+		else
+		{
+			// the opener will only partially be used - stack entry remains (truncated) and a new inline is added.
+			inl = istack->first_inline;
+			istack->delim_count -= useDelims;
+			inl->content.literal.len = istack->delim_count;
+
+			emph = useDelims == 1 ? make_emph(inl->next) : make_strong(inl->next);
+			inl->next = emph;
+
+			// remove all later openers from stack:
+                        free_openers(subj, istack);
+
+			*last = emph;
+		}
+
+		// if the closer was not fully used, move back a char or two and try again.
+		if (useDelims < numdelims)
+		{
+			subj->pos = subj->pos - numdelims + useDelims;
+			return handle_strong_emph(subj, c, last);
+		}
+
+		return NULL; // make_str(chunk_literal(""));
+	}
+
+cannotClose:
+	inl_text = make_str(chunk_dup(&subj->input, subj->pos - numdelims, numdelims));
+
+	if (can_open)
+	{
+		istack = (inline_stack*)malloc(sizeof(inline_stack));
+		istack->delim_count = numdelims;
+		istack->delim_char = c;
+		istack->first_inline = inl_text;
+		istack->previous = subj->emphasis_openers;
+		subj->emphasis_openers = istack;
 	}
 
-done:
-	free(last);
-	return result;
+	return inl_text;
 }
 
 // Parse backslash-escape or just a backslash, returning an inline.
@@ -438,9 +418,9 @@ static node_inl* handle_entity(subject* subj)
 	advance(subj);
 
 	len = houdini_unescape_ent(&ent,
-		subj->input.data + subj->pos,
-		subj->input.len - subj->pos
-	);
+				   subj->input.data + subj->pos,
+				   subj->input.len - subj->pos
+		);
 
 	if (len == 0)
 		return make_str(chunk_literal("&"));
@@ -513,8 +493,8 @@ unsigned char *clean_title(chunk *title)
 
 	// remove surrounding quotes if any:
 	if ((first == '\'' && last == '\'') ||
-		(first == '(' && last == ')') ||
-		(first == '"' && last == '"')) {
+	    (first == '(' && last == ')') ||
+	    (first == '"' && last == '"')) {
 		houdini_unescape_html_f(&buf, title->data + 1, title->len - 2);
 	} else {
 		houdini_unescape_html_f(&buf, title->data, title->len);
@@ -542,7 +522,7 @@ static node_inl* handle_pointy_brace(subject* subj)
 		return make_autolink(
 			make_str_with_entities(&contents),
 			contents, 0
-		);
+			);
 	}
 
 	// next try to match an email autolink
@@ -552,9 +532,9 @@ static node_inl* handle_pointy_brace(subject* subj)
 		subj->pos += matchlen;
 
 		return make_autolink(
-				make_str_with_entities(&contents),
-				contents, 1
-		);
+			make_str_with_entities(&contents),
+			contents, 1
+			);
 	}
 
 	// finally, try to match an html tag
@@ -598,30 +578,30 @@ static int link_label(subject* subj, chunk *raw_label)
 	char c;
 	while ((c = peek_char(subj)) && (c != ']' || nestlevel > 0)) {
 		switch (c) {
-			case '`':
-				tmp = handle_backticks(subj);
-				free_inlines(tmp);
-				break;
-			case '<':
-				tmp = handle_pointy_brace(subj);
-				free_inlines(tmp);
-				break;
-			case '[':  // nested []
-				nestlevel++;
-				advance(subj);
-				break;
-			case ']':  // nested []
-				nestlevel--;
-				advance(subj);
-				break;
-			case '\\':
-				advance(subj);
-				if (ispunct(peek_char(subj))) {
-					advance(subj);
-				}
-				break;
-			default:
+		case '`':
+			tmp = handle_backticks(subj);
+			free_inlines(tmp);
+			break;
+		case '<':
+			tmp = handle_pointy_brace(subj);
+			free_inlines(tmp);
+			break;
+		case '[':  // nested []
+			nestlevel++;
+			advance(subj);
+			break;
+		case ']':  // nested []
+			nestlevel--;
+			advance(subj);
+			break;
+		case '\\':
+			advance(subj);
+			if (ispunct(peek_char(subj))) {
 				advance(subj);
+			}
+			break;
+		default:
+			advance(subj);
 		}
 	}
 	if (c == ']') {
@@ -657,8 +637,8 @@ static node_inl* handle_left_bracket(subject* subj)
 
 	if (found_label) {
 		if (peek_char(subj) == '(' &&
-				((sps = scan_spacechars(&subj->input, subj->pos + 1)) > -1) &&
-				((n = scan_link_url(&subj->input, subj->pos + 1 + sps)) > -1)) {
+		    ((sps = scan_spacechars(&subj->input, subj->pos + 1)) > -1) &&
+		    ((n = scan_link_url(&subj->input, subj->pos + 1 + sps)) > -1)) {
 
 			// try to parse an explicit link:
 			starturl = subj->pos + 1 + sps; // after (
@@ -684,8 +664,8 @@ static node_inl* handle_left_bracket(subject* subj)
 				subj->pos = endlabel;
 				lab = parse_chunk_inlines(&rawlabel, subj->refmap);
 				result = append_inlines(make_str(chunk_literal("[")),
-						append_inlines(lab,
-							make_str(chunk_literal("]"))));
+							append_inlines(lab,
+								       make_str(chunk_literal("]"))));
 				return result;
 			}
 		} else {
@@ -714,7 +694,7 @@ static node_inl* handle_left_bracket(subject* subj)
 				subj->pos = endlabel;
 				lab = parse_chunk_inlines(&rawlabel, subj->refmap);
 				result = append_inlines(make_str(chunk_literal("[")),
-						append_inlines(lab, make_str(chunk_literal("]"))));
+							append_inlines(lab, make_str(chunk_literal("]"))));
 			}
 			return result;
 		}
@@ -736,8 +716,8 @@ static node_inl* handle_newline(subject *subj)
 		advance(subj);
 	}
 	if (nlpos > 1 &&
-			peek_at(subj, nlpos - 1) == ' ' &&
-			peek_at(subj, nlpos - 2) == ' ') {
+	    peek_at(subj, nlpos - 1) == ' ' &&
+	    peek_at(subj, nlpos - 2) == ' ') {
 		return make_linebreak();
 	} else {
 		return make_softbreak();
@@ -754,9 +734,22 @@ extern node_inl* parse_inlines_while(subject* subj, int (*f)(subject*))
 {
 	node_inl* result = NULL;
 	node_inl** last = &result;
+	node_inl* first = NULL;
 	while ((*f)(subj) && parse_inline(subj, last)) {
+	    if (!first) {
+		first = *last;
+	    }
+	}
+
+	inline_stack* istack = subj->emphasis_openers;
+	inline_stack* temp;
+	while (istack != NULL) {
+		temp = istack->previous;
+		free(istack);
+		istack = temp;
 	}
-	return result;
+
+	return first;
 }
 
 node_inl *parse_chunk_inlines(chunk *chunk, reference_map *refmap)
@@ -812,69 +805,62 @@ static int parse_inline(subject* subj, node_inl ** last)
 		return 0;
 	}
 	switch(c){
-		case '\n':
-			new = handle_newline(subj);
-			break;
-		case '`':
-			new = handle_backticks(subj);
-			break;
-		case '\\':
-			new = handle_backslash(subj);
-			break;
-		case '&':
-			new = handle_entity(subj);
-			break;
-		case '<':
-			new = handle_pointy_brace(subj);
-			break;
-		case '_':
-			if (subj->pos > 0) {
-				unsigned char prev = peek_at(subj, subj->pos - 1);
-				if (isalnum(prev) || prev == '_') {
-					new = make_str(chunk_literal("_"));
-					advance(subj);
-					break;
-				}
-			}
-
-			new = handle_strong_emph(subj, '_');
-			break;
-		case '*':
-			new = handle_strong_emph(subj, '*');
-			break;
-		case '[':
+	case '\n':
+		new = handle_newline(subj);
+		break;
+	case '`':
+		new = handle_backticks(subj);
+		break;
+	case '\\':
+		new = handle_backslash(subj);
+		break;
+	case '&':
+		new = handle_entity(subj);
+		break;
+	case '<':
+		new = handle_pointy_brace(subj);
+		break;
+	case '_':
+		new = handle_strong_emph(subj, '_', last);
+		break;
+	case '*':
+		new = handle_strong_emph(subj, '*', last);
+		break;
+	case '[':
+		new = handle_left_bracket(subj);
+		break;
+	case '!':
+		advance(subj);
+		if (peek_char(subj) == '[') {
 			new = handle_left_bracket(subj);
-			break;
-		case '!':
-			advance(subj);
-			if (peek_char(subj) == '[') {
-				new = handle_left_bracket(subj);
-				if (new != NULL && new->tag == INL_LINK) {
-					new->tag = INL_IMAGE;
-				} else {
-					new = append_inlines(make_str(chunk_literal("!")), new);
-				}
+			if (new != NULL && new->tag == INL_LINK) {
+				new->tag = INL_IMAGE;
 			} else {
-				new = make_str(chunk_literal("!"));
-			}
-			break;
-		default:
-			endpos = subject_find_special_char(subj);
-			contents = chunk_dup(&subj->input, subj->pos, endpos - subj->pos);
-			subj->pos = endpos;
-
-			// if we're at a newline, strip trailing spaces.
-			if (peek_char(subj) == '\n') {
-				chunk_rtrim(&contents);
+				new = append_inlines(make_str(chunk_literal("!")), new);
 			}
+		} else {
+			new = make_str(chunk_literal("!"));
+		}
+		break;
+	default:
+		endpos = subject_find_special_char(subj);
+		contents = chunk_dup(&subj->input, subj->pos, endpos - subj->pos);
+		subj->pos = endpos;
+
+		// if we're at a newline, strip trailing spaces.
+		if (peek_char(subj) == '\n') {
+			chunk_rtrim(&contents);
+		}
 
-			new = make_str(contents);
+		new = make_str(contents);
 	}
 	if (*last == NULL) {
 		*last = new;
-	} else {
+	} else if (new) {
 		append_inlines(*last, new);
+		*last = new;
 	}
+
 	return 1;
 }
 
@@ -890,8 +876,8 @@ void spnl(subject* subj)
 {
 	bool seen_newline = false;
 	while (peek_char(subj) == ' ' ||
-			(!seen_newline &&
-			 (seen_newline = peek_char(subj) == '\n'))) {
+	       (!seen_newline &&
+		(seen_newline = peek_char(subj) == '\n'))) {
 		advance(subj);
 	}
 }
@@ -958,4 +944,3 @@ int parse_reference_inline(strbuf *input, reference_map *refmap)
 	reference_create(refmap, &lab, &url, &title);
 	return subj.pos;
 }
-
diff --git a/src/main.c b/src/main.c
index 76a0e12..99d14f8 100644
--- a/src/main.c
+++ b/src/main.c
@@ -38,7 +38,7 @@ int main(int argc, char *argv[])
 			printf(" - CommonMark converter (c) 2014 John MacFarlane\n");
 			exit(0);
 		} else if ((strcmp(argv[i], "--help") == 0) ||
-				(strcmp(argv[i], "-h") == 0)) {
+			   (strcmp(argv[i], "-h") == 0)) {
 			print_usage();
 			exit(0);
 		} else if (strcmp(argv[i], "--ast") == 0) {
@@ -61,7 +61,7 @@ int main(int argc, char *argv[])
 
 			if (fp == NULL) {
 				fprintf(stderr, "Error opening file %s: %s\n",
-						argv[files[i]], strerror(errno));
+					argv[files[i]], strerror(errno));
 				exit(1);
 			}
 
@@ -74,4 +74,3 @@ int main(int argc, char *argv[])
 
 	return 0;
 }
-
diff --git a/src/print.c b/src/print.c
index 83f8daa..f3bd8e5 100644
--- a/src/print.c
+++ b/src/print.c
@@ -16,17 +16,17 @@ static void print_str(const unsigned char *s, int len)
 		unsigned char c = s[i];
 
 		switch (c) {
-			case '\n':
-				printf("\\n");
-				break;
-			case '"':
-				printf("\\\"");
-				break;
-			case '\\':
-				printf("\\\\");
-				break;
-			default:
-				putchar((int)c);
+		case '\n':
+			printf("\\n");
+			break;
+		case '"':
+			printf("\\\"");
+			break;
+		case '\\':
+			printf("\\\\");
+			break;
+		default:
+			putchar((int)c);
 		}
 	}
 	putchar('"');
@@ -116,13 +116,13 @@ static void print_blocks(node_block* b, int indent)
 			data = &(b->as.list);
 			if (data->list_type == ordered) {
 				printf("list (type=ordered tight=%s start=%d delim=%s)\n",
-						(data->tight ? "true" : "false"),
-						data->start,
-						(data->delimiter == parens ? "parens" : "period"));
+				       (data->tight ? "true" : "false"),
+				       data->start,
+				       (data->delimiter == parens ? "parens" : "period"));
 			} else {
 				printf("list (type=bullet tight=%s bullet_char=%c)\n",
-						(data->tight ? "true" : "false"),
-						data->bullet_char);
+				       (data->tight ? "true" : "false"),
+				       data->bullet_char);
 			}
 			print_blocks(b->children, indent + 2);
 			break;
@@ -148,7 +148,7 @@ static void print_blocks(node_block* b, int indent)
 			break;
 		case BLOCK_FENCED_CODE:
 			printf("fenced_code length=%d info=",
-				b->as.code.fence_length);
+			       b->as.code.fence_length);
 			print_str(b->as.code.info.ptr, -1);
 			putchar(' ');
 			print_str(b->string_content.ptr, -1);
diff --git a/src/references.c b/src/references.c
index 3e54b48..975bf81 100644
--- a/src/references.c
+++ b/src/references.c
@@ -55,7 +55,7 @@ static void add_reference(reference_map *map, reference* ref)
 
 	while (t) {
 		if (t->hash == ref->hash &&
-			!strcmp((char *)t->label, (char *)ref->label)) {
+		    !strcmp((char *)t->label, (char *)ref->label)) {
 			reference_free(ref);
 			return;
 		}
@@ -105,7 +105,7 @@ reference* reference_lookup(reference_map *map, chunk *label)
 
 	while (ref) {
 		if (ref->hash == hash &&
-			!strcmp((char *)ref->label, (char *)norm))
+		    !strcmp((char *)ref->label, (char *)norm))
 			break;
 		ref = ref->next;
 	}
@@ -138,4 +138,3 @@ reference_map *reference_map_new(void)
 	memset(map, 0x0, sizeof(reference_map));
 	return map;
 }
-
diff --git a/src/utf8.c b/src/utf8.c
index 6b34831..8a786b7 100644
--- a/src/utf8.c
+++ b/src/utf8.c
@@ -103,24 +103,24 @@ int utf8proc_iterate(const uint8_t *str, int str_len, int32_t *dst)
 		return -1;
 
 	switch (length) {
-		case 1:
-			uc = str[0];
-			break;
-		case 2:
-			uc = ((str[0] & 0x1F) <<  6) + (str[1] & 0x3F);
-			if (uc < 0x80) uc = -1;
-			break;
-		case 3:
-			uc = ((str[0] & 0x0F) << 12) + ((str[1] & 0x3F) <<  6)
-				+ (str[2] & 0x3F);
-			if (uc < 0x800 || (uc >= 0xD800 && uc < 0xE000) ||
-					(uc >= 0xFDD0 && uc < 0xFDF0)) uc = -1;
-			break;
-		case 4:
-			uc = ((str[0] & 0x07) << 18) + ((str[1] & 0x3F) << 12)
-				+ ((str[2] & 0x3F) <<  6) + (str[3] & 0x3F);
-			if (uc < 0x10000 || uc >= 0x110000) uc = -1;
-			break;
+	case 1:
+		uc = str[0];
+		break;
+	case 2:
+		uc = ((str[0] & 0x1F) <<  6) + (str[1] & 0x3F);
+		if (uc < 0x80) uc = -1;
+		break;
+	case 3:
+		uc = ((str[0] & 0x0F) << 12) + ((str[1] & 0x3F) <<  6)
+			+ (str[2] & 0x3F);
+		if (uc < 0x800 || (uc >= 0xD800 && uc < 0xE000) ||
+		    (uc >= 0xFDD0 && uc < 0xFDF0)) uc = -1;
+		break;
+	case 4:
+		uc = ((str[0] & 0x07) << 18) + ((str[1] & 0x3F) << 12)
+			+ ((str[2] & 0x3F) <<  6) + (str[3] & 0x3F);
+		if (uc < 0x10000 || uc >= 0x110000) uc = -1;
+		break;
 	}
 
 	if (uc < 0 || ((uc & 0xFFFF) >= 0xFFFE))
@@ -173,7 +173,7 @@ void utf8proc_case_fold(strbuf *dest, const uint8_t *str, int len)
 {
 	int32_t c;
 
-#define bufpush(x) \
+#define bufpush(x)				\
 	utf8proc_encode_char(x, dest)
 
 	while (len > 0) {
@@ -190,4 +190,3 @@ void utf8proc_case_fold(strbuf *dest, const uint8_t *str, int len)
 		len -= char_len;
 	}
 }
-