SQLFiddle is a webservice where you can setup and work with small examples of SQL on various systems (PostgreSQL, Oracle, MySQL, etc...)
I am looking for such a webservice or library that parses RegExes in various languages (Java, Perl, C#, etc...) and executes them against a given text.
RegExr is a good start but doesn't allow me to change the implementation.
The idea is to suggest this library/webservice for a problem on Stack Overflow.