Recent trends suggest that it will soon be practical to implement graphical user interfaces wherein a large part of the communication between human and computer will take the form of structured graphics, i.e., diagrams, notations, etc., which have come to be called visual languages in the literature. This thesis argues that implementation of such interfaces will be greatly facilitated by the development and use of syntax-directed translation methods for visual languages, and the embodiment of such methods in automated tools for application development, as has been done for compilers. An algebraic formalism to express syntax and semantics for visual languages is developed, and compared with similar formalisms developed by others. Tractability and algorithms for parsing are considered, and test implementations described. Several examples are presented, showing how real notations may be captured and parsed using the formalism. The design of interactive, visual language based application programs is considered in some detail, with emphasis on notations such as directed graph diagrams
