StackFormation\ValueResolver\Stage\Variable::invoke PHP Метод

    public function invoke($string)
    {
        $string = preg_replace_callback('/\\{var:([^:\\}\\{]+?)\\}/', function ($matches) {
            $vars = $this->valueResolver->getConfig()->getGlobalVars();
            if ($this->sourceBlueprint) {
                $vars = array_merge($vars, $this->sourceBlueprint->getVars());
            }
            if (!isset($vars[$matches[1]])) {
                throw new \Exception("Variable '{$matches[1]}' not found");
            }
            $value = $vars[$matches[1]];
            if (is_array($value)) {
                $value = $this->valueResolver->resolvePlaceholders($value, $this->sourceBlueprint);
            }
            if ($value == $matches[0]) {
                throw new \Exception('Direct circular reference detected');
            }
            return $value;
        }, $string);
        return $string;
    }