A Model for a Document Maintenance

We present the architecture of a system for editing formatted documents. Key among the requirements for this system are support for complex page formats and the ability to incorporate diagrams and other non-textual features. The system is interactive, using an incremental formatter to adjust the text after each change. Our model allows for extending the set of supported document objects and permits multiple views of these objects. Documents are highly structured, and relationships between structures are maintained by constraints resident in each object.