Application of graph transformation to visual languages

Graphs may be used to define visual sentences consisting of a set of visual symbols such as graphic primitives, icons or pictures, and a set of relations in between. Graph grammars are thus a natural means for defining a visual language in terms of its graph language. Using graph grammars for visual language definition, types of visual languages are tightly coupled with types of graph languages. Expressive power of a visual language type has to be considered carefully against efficiency of tools, e.g., when parsing visual languages. Context-free as well as different kinds of context-sensitive languages are considered in this chapter. Based on these concepts, two VL environment generating tools and languages—DIAGEN and GENGED—are presented that comprise generators for visual editors and parsers.

Graph transformation languages themselves form a kind of very high-level visual programming languages, where the underlying data model is a graph. These languages use graph transformation rules for manipulating graph instances on an appropriate level of abstraction. General purpose graph transformation languages PROGRES and AGG as well as special purpose languages DIAGEN and GENGED are discussed and compared with each other.