public function icon($symbol, $prefix = 'glyphicon', $tag = 'i')
    {
        $base = $prefix;
        $classes = explode(' ', $symbol);
        $prefix = array($classes[0]); // ie. only prefix the first class
        $params = '';
        if ($space = strpos($tag, ' ')) {
            $params = ' '.trim(substr($tag, $space));
            $tag = substr($tag, 0, $space);
        }
        if ($base == 'glyphicon') {
            $tag = 'span';
        }

        return $this->addClass("<{$tag}{$params}></{$tag}>", array(
            $tag => $this->prefixClasses($base, $prefix, $classes),
        ));
    }