Relational Grammars: Theory and Practice in a Visual Language Interface for Process Modeling

Relational Grammars (RGs) are one of the higher-dimensional grammar formalisms that have been proposed for representing visual languages (VLs). This paper serves as an overview of the formalism as well as a case study of its application in a visual language interface (VLI) for process modeling. Relational Grammars are a member of the context-free family of Constraint Multiset Grammars (Marriott and Meyer this volume), and several subclasses of Relational Grammars have been proposed that have been motivated by the algorithmic demands of specific applications. The applications that have been explored go beyond the exercise of recognizing visual expressions that can be constructed with standard graphical editors. Here we focus on a business process modeling tool called ShowBiz and discuss how grammatical representation and parsing is used dynamically in creating aggregations for process encapsulation and visual focusing.