Block Diagram Grammar and Structure Recognition Based on Graph Rewriting

A block diagram grammar is presented that is a formal model generating block diagrams. It is formalized as a context-sensitive graph grammar with subgraph rewriting based on subgraph isomorphism. We implement a block diagram parser that decides whether a diagram is valid for the block diagram grammar in a bottomup-parallel method, and that returns the production instance sequence for a valid diagram. A function of structure recognition is also implemented into the parser by means of template matching and subgraph rewriting. This enables the parser to find and return the structure information of series connections, parallel connections, feedback connections and so forth, in the parsed diagram.