Parser visualizations for developing grammars with yacc

This paper describes Gyacc (graphical yacc), a tool we have developed to support a graphical approach to developing languages with parser generators such as yacc. Gyacc is an interactive environment which supports the construction of context-free grammars, and provides the user with the ability to study yacc-generated parsers. We are strongly convinced that to fully teach and understand the details of a generated parser, the user or student must see it in operation. Gyacc accomplishes this by providing a set of animations which the user can select to observe different aspects of the parser as it executes.