enh(asciidoc) follow-up, support emphasis unconstrained syntax

src/languages/asciidoc.js

@@ -35,10 +35,9 @@ export default function(hljs) {
     // guard: constrained formatting mark may not be preceded by ":", ";" or
     // "}". match these so the constrained rule doesn't see them
     {
-      begin: /[:;}][*_`](?!\*)/
+      begin: /[:;}][*_`](?![*_`])/
     }
   ];
-
   const STRONG = [
     // inline unconstrained strong (single line)
     {
@@ -69,6 +68,49 @@ export default function(hljs) {
       begin: /\*[^\s]([^\n]+\n)+([^\n]+)\*/
     }
   ];
+  const EMPHASIS = [
+    // inline unconstrained emphasis (single line)
+    {
+      className: 'emphasis',
+      begin: /_{2}([^\n]+?)_{2}/
+    },
+    // inline unconstrained emphasis (multi-line)
+    {
+      className: 'emphasis',
+      begin: regex.concat(
+        /__/,
+        /((_(?!_)|\\[^\n]|[^_\n\\])+\n)+/,
+        /(_(?!_)|\\[^\n]|[^_\n\\])*/,
+        /__/
+      ),
+      relevance: 0
+    },
+    // inline constrained emphasis (single line)
+    {
+      className: 'emphasis',
+      // must not precede or follow a word character
+      begin: /\b_(\S|\S[^\n]*?\S)_(?!\w)/
+    },
+    // inline constrained emphasis (multi-line)
+    {
+      className: 'emphasis',
+      // must not precede or follow a word character
+      begin: /_[^\s]([^\n]+\n)+([^\n]+)_/
+    },
+    // inline constrained emphasis using single quote (legacy)
+    {
+      className: 'emphasis',
+      // must not follow a word character or be followed by a single quote or space
+      begin: '\\B\'(?![\'\\s])',
+      end: '(\\n{2}|\')',
+      // allow escaped single quote followed by word char
+      contains: [{
+        begin: '\\\\\'\\w',
+        relevance: 0
+      }],
+      relevance: 0
+    }
+  ];
   const ADMONITION = {
     className: 'symbol',
     begin: '^(NOTE|TIP|IMPORTANT|WARNING|CAUTION):\\s+',
@@ -171,35 +213,8 @@ export default function(hljs) {
       ADMONITION,
       ...ESCAPED_FORMATTING,
       ...STRONG,
+      ...EMPHASIS,
 
-      // TODO emphasis and code should get same treatment as strong!
-      // inline unconstrained emphasis
-      {
-        className: 'emphasis',
-        begin: /_{2}/,
-        end: /(\n{2}|_{2})/
-      },
-      // inline emphasis
-      {
-        className: 'emphasis',
-        // must not follow a word character or be followed by a single quote or space
-        begin: '\\B\'(?![\'\\s])',
-        end: '(\\n{2}|\')',
-        // allow escaped single quote followed by word char
-        contains: [{
-          begin: '\\\\\'\\w',
-          relevance: 0
-        }],
-        relevance: 0
-      },
-      // inline emphasis (alt)
-      {
-        className: 'emphasis',
-        // must not follow a word character or be followed by an underline or space
-        begin: '_(?![_\\s])',
-        end: '(\\n{2}|_)',
-        relevance: 0
-      },
       // inline smart quotes
       {
         className: 'string',

test/markup/asciidoc/constrained.expect.txt

@@ -49,3 +49,49 @@ best*</span>
 <span class="hljs-strong">*does bob
 -really-
 know best?*</span>
+
+Some emphasis on [#emphasis]<span class="hljs-emphasis">_that_</span>.
+
+The word \_underscore_ is not rendered as italic.
+
+Use the _ symbol. Read the footnotes_. You can also type_ this symbol _.
+
+An important <span class="hljs-emphasis">_wo
+rd_</span>.
+
+Not an important _wo
+
+rd_.
+
+\\blah blah <span class="hljs-emphasis">_blah_</span>.
+
+\\blah blah blah_.
+
+Does <span class="hljs-emphasis">_Bob -love- Gemma_</span>?
+
+Does <span class="hljs-emphasis">_Bob &quot;love&quot; Gemma_</span>?
+
+Does <span class="hljs-emphasis">_Bob love Gemma? Truly?_</span>
+
+There&#x27;s a colon:_directly_ before the starting formatting mark.
+
+There&#x27;s a semi-colon directly before the starting formatting mark &amp;ndash;_2018_
+
+There&#x27;s a closing curly bracket directly {before}_the starting formatting mark_.
+
+<span class="hljs-emphasis">_bl_ck_</span>-eye
+
+E = mc_2_
+
+E = _mc_2
+
+The parser is working <span class="hljs-emphasis">_99%_</span> of the time
+
+<span class="hljs-emphasis">_bob
+knows
+very
+best_</span>
+
+<span class="hljs-emphasis">_does bob
+-really-
+know best?_</span>

test/markup/asciidoc/constrained.txt

@@ -49,3 +49,49 @@ best*
 *does bob
 -really-
 know best?*
+
+Some emphasis on [#emphasis]_that_.
+
+The word \_underscore_ is not rendered as italic.
+
+Use the _ symbol. Read the footnotes_. You can also type_ this symbol _.
+
+An important _wo
+rd_.
+
+Not an important _wo
+
+rd_.
+
+\\blah blah _blah_.
+
+\\blah blah blah_.
+
+Does _Bob -love- Gemma_?
+
+Does _Bob "love" Gemma_?
+
+Does _Bob love Gemma? Truly?_
+
+There's a colon:_directly_ before the starting formatting mark.
+
+There's a semi-colon directly before the starting formatting mark –_2018_
+
+There's a closing curly bracket directly {before}_the starting formatting mark_.
+
+_bl_ck_-eye
+
+E = mc_2_
+
+E = _mc_2
+
+The parser is working _99%_ of the time
+
+_bob
+knows
+very
+best_
+
+_does bob
+-really-
+know best?_

test/markup/asciidoc/default.expect.txt

@@ -77,4 +77,4 @@ I'll join that party, too.
 <span class="hljs-section">===== Level 4 Section Title =====</span>
 <span class="hljs-section">====== Level 5 Section Title ======</span>
 
-<span class="hljs-symbol">NOTE: </span>AsciiDoc is quite cool, you should try it.
+<span class="hljs-symbol">NOTE: </span>AsciiDoc is quite cool, you should try it.

test/markup/asciidoc/default.txt

@@ -77,4 +77,4 @@ I'll join that party, too.
 ===== Level 4 Section Title =====
 ====== Level 5 Section Title ======
 
-NOTE: AsciiDoc is quite cool, you should try it.
+NOTE: AsciiDoc is quite cool, you should try it.

test/markup/asciidoc/unconstrained.expect.txt

@@ -42,3 +42,42 @@ Git[.blue]<span class="hljs-strong">**Hub**</span>
 knows
 very
 best**</span>
+
+A sentence <span class="hljs-emphasis">__ with words, and more words!
+using italic style :)__</span>.
+
+Read the little notes__.
+
+Read the little notes__
+
+This is <span class="hljs-emphasis">__italic__</span>
+
+E = <span class="hljs-emphasis">__mc__</span>2
+
+<span class="hljs-emphasis">__Bob went with _Sarah_ to the market today.__</span>
+
+<span class="hljs-emphasis">__Bob went with _Sarah_
+to the market today.__</span>
+
+There&#x27;s a colon:<span class="hljs-emphasis">__directly__</span> before the starting formatting mark.
+
+There&#x27;s a semi-colon directly before the starting formatting mark &amp;ndash;<span class="hljs-emphasis">__2018__</span>
+
+There&#x27;s a closing curly bracket directly {before}<span class="hljs-emphasis">__the starting formatting mark__</span>.
+
+<span class="hljs-emphasis">__--anything goes __</span>
+
+\\__--anything goes __
+
+\\__--anything goes __ with _ a __lot__ of underscores__
+
+<span class="hljs-emphasis">__Git__</span>Hub
+
+<span class="hljs-emphasis">__bl_ck__</span>-eye
+
+Git[.blue]<span class="hljs-emphasis">__Hub__</span>
+
+<span class="hljs-emphasis">__bob
+knows
+very
+best__</span>

test/markup/asciidoc/unconstrained.txt

@@ -42,3 +42,42 @@ Git[.blue]**Hub**
 knows
 very
 best**
+
+A sentence __ with words, and more words!
+using italic style :)__.
+
+Read the little notes__.
+
+Read the little notes__
+
+This is __italic__
+
+E = __mc__2
+
+__Bob went with _Sarah_ to the market today.__
+
+__Bob went with _Sarah_
+to the market today.__
+
+There's a colon:__directly__ before the starting formatting mark.
+
+There's a semi-colon directly before the starting formatting mark –__2018__
+
+There's a closing curly bracket directly {before}__the starting formatting mark__.
+
+__--anything goes __
+
+\\__--anything goes __
+
+\\__--anything goes __ with _ a __lot__ of underscores__
+
+__Git__Hub
+
+__bl_ck__-eye
+
+Git[.blue]__Hub__
+
+__bob
+knows
+very
+best__