An expressive, flexible railroad layout engine

Abstract

Railroad layout is a style of graph layout for an extension of directed series-parallel graphs that allows some cycles. Railroad layout is commonly used for visualizing formal grammars; we outline our in-progress approach to building a railroad layout engine that can express more of the rich variation in hand-drawn layouts and give the user more fine-grained control than any existing algorithm, extending our own prior work. Further, we claim that railroad layout can apply to other domains with similar structure, such as pretty-printing code and visualizing structured control-flow graphs. We describe how we plan to evaluate our claims. We are eager to present and receive feedback on visualization work that so far has largely been limited to the programming languages community.