R-regexp
the regular expression develop / test utility
This tool is created for fast developing and testing of your regular expressions. It's useable also when you need one-time processing of text by using regular expression due to it's replace function.
The most useable feature for your developing needs is treeview of found matches. When you click on some of items in this treeview, then relevant text piece is selected so, you can easily track problems with your regexp.
Program is running on machines with Microsoft .NET framework 1.1 and is using System.Text.regex internally. So it's fully compatible with that .NET class.
You can download preview version of r-regexp here.