GenEd-an editor with generic semantics for formal reasoning about visual notations

We describe the object-oriented editor GenEd supporting the design of specifications for visual notations. Prominent features of GenEd are: it is generic, i.e. domain-specific syntax and semantics are specified by users; built-in parser for actual drawings, driven by formal specifications; powerful reasoning capabilities about diagrams and their specification. GenEd's specification language is based on a fully formalized theory for describing visual notations. Three examples, place-transition Petri nets, entity-relationship diagrams, and a small GIS application are presented.