PHP Web Components

I read about W3C Web Components spec and JavaScript's libraries like polymer.js and others, so I tried to find something similar in PHP, but with no luck.

So I wrote a tiny class to work with custom tags in PHP and I'd like to know what do you think about it. Is the idea somehow reasonable?

Here is the Github repo.

public static function loadString($string, array $context = array()) {
    $context = new Context($context);
    //eval the first time
    $string = self::evall($string, $context);
    //eval 'til there are custom tags
    while ($matches = self::matchWebComp($string)) {            
        $context = new Context($matches);            
        $context->setArray(Context::fromAttributesString($context->attributesList)->toArray());

        $webComp = self::getWebCompDefinition($context->tag);
        $webComp = self::evall($webComp, $context);
        $string = str_replace($context->match, $webComp, $string);
    }
    return $string;
}

public static function evall($string, Context $context = NULL) {
    ob_start();
    eval('; ?>' . $string);
    return ob_get_clean();
}

public static function matchWebComp($string) {
      //match <a-tag [attributes]>[inner html]</a-tag>
      if (preg_match('/<(?P<tag>\w+-[\w\-]+)( *.*)>([\s\S]*)<\/(?P=tag)>/U', $string, $matches)) {
          return array(
              'match' => $matches[0],
              'tag' => $matches[1],
              'attributesList' => $matches[2],
              'innerHtml' => $matches[3]
          );
      }
}