function Renderer() {

  /**
   * Renderer#rules -> Object
   *
   * Contains render rules for tokens. Can be updated and extended.
   *
   * ##### Example
   *
   * ```javascript
   * var md = require('markdown-it')();
   *
   * md.renderer.rules.strong_open  = function () { return '<b>'; };
   * md.renderer.rules.strong_close = function () { return '</b>'; };
   *
   * var result = md.renderInline(...);
   * ```
   *
   * Each rule is called as independed static function with fixed signature:
   *
   * ```javascript
   * function my_token_render(tokens, idx, options, env, renderer) {
   *   // ...
   *   return renderedHTML;
   * }
   * ```
   *
   * See [source code](https://github.com/markdown-it/markdown-it/blob/master/lib/renderer.js)
   * for more details and examples.
   **/
  this.rules = assign({}, default_rules);
}
new Renderer()

Creates new [[Renderer]] instance and fill [[Renderer#rules]] with defaults.