A prerequisite for using such tools, however, is that a *model importer* exists for the programming language (or languages) in which the system is developed. Constructing a model importer from scratch is a major effort, and the large up-front investment hampers initiatives for many commercial tool builders [LV01, BBC+10]. Adapting an existing parser for the host language is often not an option especially for proprietary and legacy languages, or for sources mixed from different languages.