allow backslash-escapes in link text, href, title and link definition…

… references.

InlineLexer.escapes() handles markdown escapes sequences.
TODO handle escapes everywhere in the document.

lib/marked.js

@@ -397,7 +397,7 @@ Lexer.prototype.token = function(src, top) {
     if (top && (cap = this.rules.def.exec(src))) {
       src = src.substring(cap[0].length);
       if (cap[3]) cap[3] = cap[3].substring(1, cap[3].length - 1);
-      tag = cap[1].toLowerCase();
+      tag = InlineLexer.escapes(cap[1].toLowerCase());
       if (!this.tokens.links[tag]) {
         this.tokens.links[tag] = {
           href: cap[2],
@@ -508,9 +508,11 @@ var inline = {
   text: /^[\s\S]+?(?=[\\<!\[`*]|\b_| {2,}\n|$)/
 };
 
+
+inline._escapes = /\\([!"#$%&'()*+,\-./:;<=>?@\[\]\\^_`{|}~])/g;
+
 inline._scheme = /[a-zA-Z][a-zA-Z0-9+.-]{1,31}/;
 inline._email = /[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+(@)[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)+(?![-_])/;
-
 inline.autolink = edit(inline.autolink)
   .replace('scheme', inline._scheme)
   .replace('email', inline._email)
@@ -524,7 +526,7 @@ inline.tag = edit(inline.tag)
   .getRegex();
 
 inline._inside = /(?:\[[^\]]*\]|\\[\[\]]|[^\[\]]|\](?=[^\[]*\]))*/;
-inline._href = /\s*<?(\S*?)>?(?:\s+['"]([\s\S]*?)['"])?\s*/;
+inline._href = /\s*<?((?:\\[()]?|[^\s()\\])*?)>?(?:\s+['"]([\s\S]*?)['"])?\s*/;
 
 inline.link = edit(inline.link)
   .replace('inside', inline._inside)
@@ -693,8 +695,8 @@ InlineLexer.prototype.output = function(src) {
       src = src.substring(cap[0].length);
       this.inLink = true;
       out += this.outputLink(cap, {
-        href: cap[2],
-        title: cap[3]
+        href: InlineLexer.escapes(cap[2]),
+        title: InlineLexer.escapes(cap[3])
       });
       this.inLink = false;
       continue;
@@ -704,7 +706,7 @@ InlineLexer.prototype.output = function(src) {
     if ((cap = this.rules.reflink.exec(src))
         || (cap = this.rules.nolink.exec(src))) {
       src = src.substring(cap[0].length);
-      link = (cap[2] || cap[1]).replace(/\s+/g, ' ');
+      link = InlineLexer.escapes(cap[2] || cap[1]).replace(/\s+/g, ' ');
       link = this.links[link.toLowerCase()];
       if (!link || !link.href) {
         out += cap[0].charAt(0);
@@ -767,6 +769,10 @@ InlineLexer.prototype.output = function(src) {
   return out;
 };
 
+InlineLexer.escapes = function(text) {
+  return text ? text.replace(InlineLexer.rules._escapes, '$1') : text;
+}
+
 /**
  * Compile Link
  */