The Graph Programming Language GP

GP (for Graph Programs) is a rule-based, nondeterministic programming language for solving graph problems at a high level of abstraction, freeing programmers from handling low-level data structures. The core of GP consists of four constructs: single-step application of a set of conditional graph-transformation rules, sequential composition, branching and iteration. This paper gives an overview on the GP project. We introduce the language by discussing a sequence of small programming case studies, formally explain conditional rule schemata which are the building blocks of programs, and present a semantics for GP in the style of structural operational semantics. A special feature of the semantics is how it uses the notion of finitely failing programs to define powerful branching and iteration commands. We also describe GP’s prototype implementation.