This section describes the two main aspects of user interaction, displaying messages and querying the user. We will deal with these two issues in turn.
| • Message Processing: | Message Processing | |
| • Message Handling Predicates: | Message Handling Predicates | |
| • Query Processing: | Query Processing | |
| • Query Handling Predicates: | Query Handling Predicates | |
| • Message Summary: | Predicate Summary |