Visual conditional attributed rewriting systems in visual language specification

In order to manage visual interaction problems, we deepen a formalisation of visual languages, based on the notion of visual sentence, introduced in a previous paper (Bottoni et al., 1995). Visual conditional attributed rewriting systems (vCARWs) are proposed for the specification of visual languages. We argue that vCARWs can be viewed as a generalisation of conditional set rewrite systems, which in turn were shown to be as expressive as textual context-free grammars, picture layout grammars, and constraint multiset grammars. Last, we outline a procedure to translate visual gestures into visual sentences according to vCARW rules.