fix #1533 syntax highlighting of markdown links

lib/ace/mode/_test/text_markdown.txt

@@ -14,7 +14,7 @@ test: only space between #s is not a valid header
 #  #
 
 # test links  [Cloud9 IDE](http://www.c9.io/) #
-* [demo](http://ajaxorg.github.com/ace/) 
+* [demo](http://ajaxorg.github.com/ace/) [+](escape(\) ) [+](a "title") [+](a "space" )
 * usually *work* fine (_em_)
 in lists
 

lib/ace/mode/_test/tokens_markdown.json

@@ -64,7 +64,26 @@
   ["text","]("],
   ["markup.underline","http://ajaxorg.github.com/ace/"],
   ["text",")"],
-  ["list"," "]
+  ["list"," "],
+  ["text","["],
+  ["string","+"],
+  ["text","]("],
+  ["markup.underline","escape(\\) "],
+  ["text",")"],
+  ["list"," "],
+  ["text","["],
+  ["string","+"],
+  ["text","]("],
+  ["markup.underline","a"],
+  ["string"," \"title\""],
+  ["text",")"],
+  ["list"," "],
+  ["text","["],
+  ["string","+"],
+  ["text","]("],
+  ["markup.underline","a"],
+  ["string"," \"space\" "],
+  ["text",")"]
 ],[
    "listblock",
   ["markup.list","* "],

lib/ace/mode/markdown_highlight_rules.js

@@ -32,12 +32,17 @@ define(function(require, exports, module) {
 "use strict";
 
 var oop = require("../lib/oop");
+var lang = require("../lib/lang");
 var TextHighlightRules = require("./text_highlight_rules").TextHighlightRules;
 var JavaScriptHighlightRules = require("./javascript_highlight_rules").JavaScriptHighlightRules;
 var XmlHighlightRules = require("./xml_highlight_rules").XmlHighlightRules;
 var HtmlHighlightRules = require("./html_highlight_rules").HtmlHighlightRules;
 var CssHighlightRules = require("./css_highlight_rules").CssHighlightRules;
 
+var escaped = function(ch) {
+    return "(?:[^" + lang.escapeRegExp(ch) + "\\\\]|\\\\.)*";
+}
+
 function github_embed(tag, prefix) {
     return { // Github style block
         token : "support.function",
@@ -104,15 +109,15 @@ var MarkdownHighlightRules = function() {
             regex : "^([ ]{0,3}\\[)([^\\]]+)(\\]:\\s*)([^ ]+)(\\s*(?:[\"][^\"]+[\"])?(\\s*))$"
         }, { // link by reference
             token : ["text", "string", "text", "constant", "text"],
-            regex : "(\\[)((?:[[^\\]]*\\]|[^\\[\\]])*)(\\][ ]?(?:\\n[ ]*)?\\[)(.*?)(\\])"
+            regex : "(\\[)(" + escaped("]") + ")(\\]\s*\\[)("+ escaped("]") + ")(\\])"
         }, { // link by url
             token : ["text", "string", "text", "markup.underline", "string", "text"],
-            regex : "(\\[)"+
-                    "(\\[[^\\]]*\\]|[^\\[\\]]*)"+
-                    "(\\]\\([ \\t]*)"+
-                    "(<?(?:(?:[^\\(]*?\\([^\\)]*?\\)\\S*?)|(?:.*?))>?)"+
-                    "((?:[ \t]*\"(?:.*?)\"[ \\t]*)?)"+
-                    "(\\))"
+            regex : "(\\[)(" +                                        // [
+                    escaped("]") +                                    // link text
+                    ")(\\]\\()"+                                      // ](
+                    '((?:[^\\)\\s\\\\]|\\\\.|\\s(?=[^"]))*)' +        // href
+                    '(\\s*"' +  escaped('"') + '"\\s*)?' +            // "title"
+                    "(\\))"                                           // )
         }, { // strong ** __
             token : "string",
             regex : "([*]{2}|[_]{2}(?=\\S))(.*?\\S[*_]*)(\\1)"