Hierarchical program diagram editor based on attribute graph grammar

The hierarchical program diagram editor is a tool for visual program environments. We propose a model of a syntax-directed diagram editor using an attribute graph grammar We formalize and define editor commands by using productions of the attribute graph grammar which defines the hierarchical program diagram. This guarantees that any diagram that is grammatically correct can be generated and that there will be no syntax errors in the program generation and editing processes with the editor. We have implemented our editor based on the editor command definitions. The system is the first practical program diagram editor supporting complete syntax-directed commands and efficient automatic layouts by using attribute graph grammars. The methods should be applicable to development environments for various tree-structured diagrams