Specifying the Geometric Machine visual language

This paper summarizes an experiment in the formal specification of the visual language for the Geometric Machine model [3], denoted by GMVL. The specification follows the approach proposed in the GENGED project, of the T U. Berlin [1]. 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 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.