code: function(name, context){
    var cls = context.cls;
    var domline = context.domline;
    var headingType = /(?:^| )heading:([A-Za-z0-9]*)/.exec(cls);
    var tagIndex;
    
    if (headingType) tagIndex = _.indexOf(tags, headingType[1]);
    
    if (tagIndex !== undefined && tagIndex >= 0){
      
      var tag = tags[tagIndex];
      var modifier = {
        preHtml: '<' + tag + '>',
        postHtml: '</' + tag + '>',
        processedMarker: true
      };
      return [modifier];
    }
    return [];
  }
docs: Here we convert the class heading:h1 into a tag