The specification of visual language syntax

Abstract

An approach for building a language-independent visual programming environment based on syntax specifications is described. A model for specifying the syntax of visual languages, picture layout grammars, is described, and an example is given of how these grammars are used to define the syntax of a visual language. A spatial parser is an algorithm for recovering the underlying structure of a visual program from the picture. A spatial parser for visual languages whose syntax is specified by a picture layout grammar was implemented. This parser forms the basis of a visual programming environment.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>