[SOLVED] Extend class in PHP

Extend class in PHP

I am trying to extend a class:

class CustomParsedown extends Parsedown {
    protected function blockComment($Line) { return; }
    protected function blockCommentContinue($Line, array $Block) { return; }
    protected function blockHeader($Line) { return; }
    protected function blockSetextHeader($Line, array $Block = NULL) { return; }
}

function markdown($markdown) {
    return CustomParsedown::instance()->setMarkupEscaped(true)->text($markdown);
}

If I run markdown() with markdown from another page, the changes in the code do not go into effect. For example, I can still create a heading. Am I extending the class correctly?

Solution

It looks like Parsedowns static function instance() is referencing $instance = new self(); which means it will instantiate a new Parsedown class and not your extending class.

Try duplicating their instance method into your class, I've also changed new self into new static.

class CustomParsedown extends Parsedown {
  static function instance($name = 'default')
  {
      if (isset(self::$instances[$name]))
      {
          return self::$instances[$name];
      }
      $instance = new static();
      self::$instances[$name] = $instance;
      return $instance;
  }
  private static $instances = array();
}

https://github.com/erusev/parsedown/blob/master/Parsedown.php