feat(backslashEscapesHTMLTags): backslash escapes HTML tags

Add support for HTML tag escaping with backslash

Closes #374

README.md

@@ -198,7 +198,7 @@ var defaultOptions = showdown.getDefaultOptions();
 
  * **noHeaderId**: (boolean) [default false] Disable the automatic generation of header ids. Setting to true overrides **prefixHeaderId**
 
- * **customizedHeaderId**: (boolean) [default false] Use text in curly braces as header id.
+ * **customizedHeaderId**: (boolean) [default false] Use text in curly braces as header id. (since v1.7.0)
    Example:
    ```
    ## Sample header {real-id}     will use real-id as id
@@ -328,7 +328,9 @@ var defaultOptions = showdown.getDefaultOptions();
 
    NOTE: Prior to version 1.6.1, emails would always be obfuscated through dec and hex encoding.
 
- * **openLinksInNewWindow**: (boolean) [default false] Open all links in new windows (by adding the attribute `target="_blank"` to `<a>` tags)
+ * **openLinksInNewWindow**: (boolean) [default false] Open all links in new windows (by adding the attribute `target="_blank"` to `<a>` tags) (since v1.7.0)
+
+ * **backslashEscapesHTMLTags**: (boolean) [default false] Support for HTML Tag escaping. ex: `\<div>foo\</div>` (since v1.7.2)
 
 **NOTE**: Please note that until version 1.6.0, all of these options are ***DISABLED*** by default in the cli tool.
  

dist/showdown.js

@@ -127,6 +127,11 @@ function getDefaultOpts (simple) {
       defaultValue: false,
       description: 'Open all links in new windows',
       type: 'boolean'
+    },
+    backslashEscapesHTMLTags: {
+      defaultValue: false,
+      description: 'Support for HTML Tag escaping. ex: \<div>foo\</div>',
+      type: 'boolean'
     }
   };
   if (simple === false) {
@@ -1940,14 +1945,26 @@ showdown.subParser('hashHTMLBlocks', function (text, options, globals) {
         return '\n\n¨K' + (globals.gHtmlBlocks.push(txt) - 1) + 'K\n\n';
       };
 
+  if (options.backslashEscapesHTMLTags) {
+    // encode backslash escaped HTML tags
+    text = text.replace(/\\<(\/?[^>]+?)>/g, function (wm, inside) {
+      return '&lt;' + inside + '&gt;';
+    });
+  }
+
+  // hash HTML Blocks
   for (var i = 0; i < blockTags.length; ++i) {
 
     var opTagPos,
-        rgx1     = new RegExp('^ {0,3}<' + blockTags[i] + '\\b[^>]*>', 'im'),
+        rgx1     = new RegExp('^ {0,3}(<' + blockTags[i] + '\\b[^>]*>)', 'im'),
         patLeft  = '<' + blockTags[i] + '\\b[^>]*>',
         patRight = '</' + blockTags[i] + '>';
     // 1. Look for the first position of the first opening HTML tag in the text
     while ((opTagPos = showdown.helper.regexIndexOf(text, rgx1)) !== -1) {
+
+      // if the HTML tag is \ escaped, we need to escape it and break
+
+
       //2. Split the text in that position
       var subTexts = showdown.helper.splitAtIndex(text, opTagPos),
       //3. Match recursively

src/options.js

@@ -125,6 +125,11 @@ function getDefaultOpts (simple) {
       defaultValue: false,
       description: 'Open all links in new windows',
       type: 'boolean'
+    },
+    backslashEscapesHTMLTags: {
+      defaultValue: false,
+      description: 'Support for HTML Tag escaping. ex: \<div>foo\</div>',
+      type: 'boolean'
     }
   };
   if (simple === false) {

src/subParsers/hashHTMLBlocks.js

@@ -48,14 +48,26 @@ showdown.subParser('hashHTMLBlocks', function (text, options, globals) {
         return '\n\n¨K' + (globals.gHtmlBlocks.push(txt) - 1) + 'K\n\n';
       };
 
+  if (options.backslashEscapesHTMLTags) {
+    // encode backslash escaped HTML tags
+    text = text.replace(/\\<(\/?[^>]+?)>/g, function (wm, inside) {
+      return '&lt;' + inside + '&gt;';
+    });
+  }
+
+  // hash HTML Blocks
   for (var i = 0; i < blockTags.length; ++i) {
 
     var opTagPos,
-        rgx1     = new RegExp('^ {0,3}<' + blockTags[i] + '\\b[^>]*>', 'im'),
+        rgx1     = new RegExp('^ {0,3}(<' + blockTags[i] + '\\b[^>]*>)', 'im'),
         patLeft  = '<' + blockTags[i] + '\\b[^>]*>',
         patRight = '</' + blockTags[i] + '>';
     // 1. Look for the first position of the first opening HTML tag in the text
     while ((opTagPos = showdown.helper.regexIndexOf(text, rgx1)) !== -1) {
+
+      // if the HTML tag is \ escaped, we need to escape it and break
+
+
       //2. Split the text in that position
       var subTexts = showdown.helper.splitAtIndex(text, opTagPos),
       //3. Match recursively

test/features/#374.escape-html-tags.html

@@ -0,0 +1 @@
+<p>&lt;div&gt;foo&lt;/div&gt;</p>

test/features/#374.escape-html-tags.md

@@ -0,0 +1 @@
+\<div>foo\</div>

test/node/testsuite.features.js

@@ -80,6 +80,8 @@ describe('makeHtml() features testsuite', function () {
         converter = new showdown.Converter({customizedHeaderId: true});
       } else if (testsuite[i].name === '#378.simplifiedAutoLinks-with-excludeTrailingPunctuationFromURLs') {
         converter = new showdown.Converter({simplifiedAutoLink: true, excludeTrailingPunctuationFromURLs: true});
+      } else if (testsuite[i].name === '#374.escape-html-tags') {
+        converter = new showdown.Converter({backslashEscapesHTMLTags: true});
       } else if (testsuite[i].name === '#379.openLinksInNewWindow-breaks-em-markdup') {
         converter = new showdown.Converter({openLinksInNewWindow: true});
       } else {