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UBC Theses and Dissertations

An interactive graphical program for specification and application of web rewriting rules Ng, William Pak Hung


Web grammars are a general and flexible method for "picture" description in computer graphics. They apply the rewriting procedure typical of string grammars to general directed graphs or "webs". An interactive graphical system is implemented to provide an easy and convenient way to manipulate and specify a web in a natural manner. This project is based on a system implemented by Pat Conroy. The system is written in ALGOLW. The graphical terminal used to display the webs is an Adage Graphical Terminal ( AGT for short ) which is connected to a main computer, an IBM 360/67 by telephone lines. There are instruments such as light-pen, function keys, foot pedals and dials to assist the interaction between the user and the AGT. In this project, a solution to the problem of replacing a subweb by another on the display screen is attemped.

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