The specification of visual language syntax

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.<
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