Designing and prototyping in GRADS

The authors present a graphical approach to software design that supports specification, prototyping, stepwise refinement and analysis of designs. The approach is based on a formal model from language and graph theory and has a practical implementation, the Graphical Design System [GRADS]. The examples given demonstrate that dataflow methods of design can be conveniently combined with state machine diagrams within a prototyping environment. The authors show how complex designs may be decomposed into independent modules. Finally they include an example formal specification of a system based on the same graphical design approach