Specifying the geometric machine visual language

This paper summarizes an experiment in the formal specification of the visual language for the geometric machine model, denoted by GMVL. The specification follows the approach proposed in the GENGED project, of the T. U. Berlin by R. Bardohl and C. Ermel (2001). In the GMLV, supported by a visual alphabet and a visual grammar, a process constructor is represented by a graph transformation related to a rule application in the visual grammar. The syntactical level includes an abstract syntax, related to the logical level of the graphic structures, and a concrete syntax, concerned with the graphical layout. Some of the important benefits from a visual approach, that overhaul and stimulate the programming the GM model, are emphasized in the spacial representation of functional composition and recursive definitions of parallel and non-deterministic processes.