Priority-Independent Rewrite Systems for Pointer-based Data-Structures

20 pagesWe define a syntactic class of graphs and graph rewrite systems for which the normal forms are independent from the order in which the nodes are reduced. This result, that is not covered by existing approaches in graph rewriting, allows us to devise simple confluence criteria and efficient normalization algorithms. It is based on a static analysis of the rewrite system, including a thorough analysis of the shape of the graphs generated during the rewriting process. The considered graphs naturally encode pointer-based data structures that are commonly used in practical programming and the rewrite rules can simulate any elementary transformation on these data structures (edge redirection, node relabeling etc.)