DECS, a meta-CASE tool with visually-oriented constraint definition features

DECS is a meta-CASE tool that generates interactive software design diagram editors based on specifications provided by a tool designer. A specification consists of a set of editor element types (vertices, edges) plus constraints on the use of those types. We present visually-oriented techniques for constraint definition and the language used for this purpose. We argue that the DECS approach offers flexibility and reduces the complexity of the constraint specification task.