The Regex Coach is a graphical application developed by Edi Weitz and released on January 2008. The program enables users to test and experiment with regular expressions made with PERL-compatible programs. These include PERL-compatible toolkits like CL-PPCRE and PCRE. PERL-compatible programs include PHP, Python, and Apache.
The Regex Coach has several capabilities. It allows users to match expressions regularly used with a specific target string. The program can likewise determine when parts of a target string matches with arbitrary parts of regular expressions or captured register groups. It also allows users to check each matched string one at a time. The program also offers to convert regular expressions into English. It likewise creates a parse tree graphical representation of the regular expression. The program also comes with real-time support enabling users to check developments in the application whenever there is a change in the parts.
The Regex Coach graphical user interface contains two main panes—the regex pane and the target pane. Directly below them are the regex message area and the target message area, respectively. Users may type in the regular expressions to be matched on the regex pane, and the target string on the target pane. In turn, the target message area will show when there is a match. However, the regex message area will be empty most of the time, unless there is a syntax error in the regular expression. In this case, the regex message area will flash a red message.