A framework for formally defining the syntax of visual languages

This paper outlines a framework for syntax definition. The purpose of the framework is to enable the construction of grammatical formalisms which are suitable for defining the syntax of visual languages. The paper considers a number of existing formalisms and illustrates how they may be expressed within the framework. The framework is then used to design a new grammatical formalism for defining the syntax of languages of Venn diagrams. It is concluded that the framework demonstrates potential to aid the development of grammatical formalisms for defining the syntax of visual languages