P t is a visual and interactive tool for parsing and transforming grammars.
In the the graphical visualization, a parse tree for the derivation is shown with each node representing a symbol or a variable. In the transformations, a graphical representation is used to help the user determine new productions in the removal of unit and useless productions. The help covers how to use P t and carry out the removals and conversions. The HTML help is now available online. We have applet versions available that you can try out on Netscape, but be aware that they don't work as well as the application.