RegeXeX: An Interactive System Providing Regular Expression Exercises

RegeXeX was created by Dr. Chris Brown and LT Eric Hardisty to help students learn to write regular expressions.

Students are given prose descriptions of regular languages and asked to provide a regular expression that defines the language. What is novel in this system is the type of feedback: students are not merely told that a submitted regular expression is wrong, they are given examples of strings that the expression either matches and shouldn't or does not match and should, and asked to try again.

The following screenshots were obtained from a system running SuSE Linux 10.1, though RegeXeX also runs on Windows, Solaris 10 and Mac OS X.

RegeXeX's main interface, with an example problem showing the feedback RegeXeX provides.

RegeXeX will also attempt to show the student why their regular expression matches extra strings by placing the matched symbols of the extra strings under the portion of the student's regular expression responsible for matching it.
RegeXeX was written in C++ using the freely available Qt libraries for its GUI. The source code, a release version for Windows, along with an example problem set, instructions on how to build RegeXeX and create problem sets can be obtained from our Sourceforge site.

LT Eric Hardisty
Last modified: Sun Aug 26 15:42:35 EDT 2007