A Graphical Semantics for Graphical Transformation Languages

Understanding the semantics of graphical representations of textual programs can be difficult because the reader must understand both the relationship between the graphic and textual representations as well as the semantics of the underlying textual program. We present a framework for describing the semantics of graphical program representations in graphical terms through transformations, thus reducing the need to understand the textual form and its relation to the graphical form. In addition, our graphical semantics framework potentially offers the same advantages for understanding semantics that visual program representations offer for understanding programs. In order to illustrate our framework, we describe the semantics of control structures in VIPR, a graphical program representation for imperative languages such as C and Tcl.