The following applet lets students learn about context free grammars. Try it by playing with the grammar preloaded in the grammar pane or click on "Access Grammar Tools" and select a new grammar for use. Of course, you may enter your own grammar as well. One hint: when the directions say to "select a node to expand" you must left click on a nonterminal in the parse tree to which you wish to apply a rule.
Other than recent a recent version of a standard browser and the Java Runtime Environment, no special software is needed to run this applet.
This applet was the work of Teresa Lutey, who worked on the applet under support from the National Science Foundation while completing her Master's project.