A mechanism for specifying the structure of large, layered, object-oriented programs

Modern programming practices often result in programs that have layered structure: the use of levels of abstraction, layers of protection or multiple views of objects all give rise to layered programs. This paper describes a structuring mechanism, called the grid, especially designed to specify, represent, document and enforce the structure of large, layered programs. A grid specification identifies the program layers explicitly, and specifies program structure and access restrictions in terms of them. It emphasizes human readability and uses some novel techniques to make the global structure of large programs clear and visible.