directive: add support for regular expression custom directive.

Example:
The custom directive {name: /\?(php|=).*/, start: '<', end: '>'} will match any directive with <?php ?> or <?= ?> pattern

Author: oantoro

README.md

@@ -82,7 +82,7 @@ Tag objects can contain three keys. The `tag` key takes the name of the tag as t
 ### `directives`
 Type: `Array`  
 Default: `[{name: '!doctype', start: '<', end: '>'}]`   
-Description: *Adds processing of custom directives*  
+Description: *Adds processing of custom directives. Note: The property ```name``` in custom directives can be ```String``` or ```RegExp``` type*  
 
 ## License
 

index.js

@@ -29,11 +29,20 @@ function postHTMLParser(html, options) {
         var directives = options.directives || defaultDirectives;
         var last = bufArray.last();
 
+        var tagName;
         for (var i = 0; i < directives.length; i++) {
             var directive = directives[i];
             var directiveText = directive.start + data + directive.end;
+            var isDirective = false;
 
-            if (name.toLowerCase() === directive.name) {
+            tagName = name.toLowerCase();
+            if ((directive.name instanceof RegExp) && directive.name.test(tagName)) {
+                isDirective = true;
+            } else if (tagName === directive.name) {
+                isDirective = true;
+            }
+
+            if (isDirective) {
                 if (!last) {
                     results.push(directiveText);
                     return;

test/test.js

@@ -131,6 +131,15 @@ describe('PostHTML-Parser test', function() {
         expect(parser('<?php echo "Hello word"; ?>', customDirectives)).to.eql(['<?php echo "Hello word"; ?>']);
     });
 
+    it('should be parse regular expression directive', function() {
+        var customDirectives = {directives: [
+            {name: /\?(php|=).*/, start: '<', end: '>'}
+        ]};
+
+        expect(parser('<?php echo "Hello word"; ?>', customDirectives)).to.eql(['<?php echo "Hello word"; ?>']);
+        expect(parser('<?="Hello word"?>', customDirectives)).to.eql(['<?="Hello word"?>']);
+    });
+
     it('should be parse directives and tag', function() {
         var customDirectives = {directives: [
             {name: '!doctype', start: '<', end: '>'},