A model for the specification and interpretation of visual languages

A model for the specification of icon systems is proposed, and a general-purpose icon interpreter is presented, based on attribute grammars. In the model, the underlying context-free grammar is a picture grammar that expresses the syntactic aspects of the icon systems. An attribute evaluator computes the meaning of a given icon sentence by evaluating the designated s-attribute of the nonterminal on the root of the parse tree. As semantic rules are actually domain-independent rule schemata, during the attribute evaluation a domain-specific knowledge base is consulted. The meaning of the ionic sentence is expressed in terms of conceptual tree graphs, which are well-suited for later execution. The design of the model is based on the theory of generalized icons. The system diagram of the icon interpreter is presented. The icon dictionary, the domain specific knowledge base, and the attribute grammar are described.<>