showdownjs/showdown

showdown.subParser('makehtml.hashHTMLBlocks', function (text, options, globals) {
  'use strict';
  text = globals.converter._dispatch('makehtml.hashHTMLBlocks.before', text, options, globals).getText();

  var blockTags = [
        'pre',
        'div',
        'h1',
        'h2',
        'h3',
        'h4',
        'h5',
        'h6',
        'blockquote',
        'table',
        'dl',
        'ol',
        'ul',
        'script',
        'noscript',
        'form',
        'fieldset',
        'iframe',
        'math',
        'style',
        'section',
        'header',
        'footer',
        'nav',
        'article',
        'aside',
        'address',
        'audio',
        'canvas',
        'figure',
        'hgroup',
        'output',
        'video',
        'details',
        'p'
      ],
      repFunc = function (wholeMatch, match, left, right) {
        var txt = wholeMatch;
        // check if this html element is marked as markdown
        // if so, it's contents should be parsed as markdown
        if (left.search(/\bmarkdown\b/) !== -1) {
          txt = left + globals.converter.makeHtml(match) + right;
        }
        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'),
        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
          newSubText1 = showdown.helper.replaceRecursiveRegExp(subTexts[1], repFunc, patLeft, patRight, 'im');

      // prevent an infinite loop
      if (newSubText1 === subTexts[1]) {
        break;
      }
      text = subTexts[0].concat(newSubText1);
    }
  }
  // HR SPECIAL CASE
  text = text.replace(/(\n {0,3}(<(hr)\b([^<>])*?\/?>)[ \t]*(?=\n{2,}))/g,
    showdown.subParser('makehtml.hashElement')(text, options, globals));

  // Special case for standalone HTML comments
  text = showdown.helper.replaceRecursiveRegExp(text, function (txt) {
    return '\n\n¨K' + (globals.gHtmlBlocks.push(txt) - 1) + 'K\n\n';
  }, '^ {0,3}<!--', '-->', 'gm');

  // PHP and ASP-style processor instructions (<?...?> and <%...%>)
  text = text.replace(/\n\n( {0,3}<([?%])[^\r]*?\2>[ \t]*(?=\n{2,}))/g,
    showdown.subParser('makehtml.hashElement')(text, options, globals));

  text = globals.converter._dispatch('makehtml.hashHTMLBlocks.after', text, options, globals).getText();
  return text;
});