protected function parseInstructions($content, $instruction)
    {
        $twig    = new Twig_Environment(new Twig_Loader_String());
        $sources = $this->getStringsBetween($content, "[[{$instruction}]]", "[[/{$instruction}]]");
        foreach ($sources as $source) {
            $toReplace = $source;
            $source    = $this->clearCondition($source);
            if ($source === '') {
                return $content;
            }
            $variables    = $this->extractVariables($source);
            $renderParams = [];

            foreach (array_keys($variables) as $index => $key) {
                $localVariable                = 'var_' . $index;
                $source                       = str_replace($key, $localVariable, $source);
                $renderParams[$localVariable] = $variables[$key];
            }
            $content = str_replace(["[[{$instruction}]]", "[[/{$instruction}]]", $toReplace], ['', '', $twig->render($source, $renderParams)], $content);
        }
        return $content;
    }