Oyster helps you interactively build and test regular expressions--which aren't the easiest things to build and debug--storing each "pearl" in an easy-to-access library.

With powerful syntax highlighting, dynamic updates of matches, and the results of replacement patterns in test text, it has never been easier to build and test your regular expressions. Once you've got it just the way you like it, Oyster lets you copy the code in one of 11 languages onto the clipboard or by dragging out the pip into your desired editor. Starting with Dash 1.8.5 (coming August 2013) you can even save your regular expression as a snippet in Dash's library. You're not alone either: Oyster has built-in integration with Oyster Farm, an online repository for pearls. You can download something that seems to fit the bill for you, and tweak it into what you would like. You can even share your changes, or post entirely new pearls of your own.

Key features:

• Keep a library of regular expressions, match tests, and replacement patterns (locally or in iCloud)
• Download and share pearls in the oyster farm
• Interactive highlighting of regular expression, matches, and pattern application
• Match highlighting includes group matches within overall match
• Generate code for C#, Java, JavaScript, JSP, Objective-C (NSRegularExpression and NSPredicate), PHP, Ruby, Pearl, Python, and TCL/TK
• Handy regex reference sheet to help you tune your regular expression

• Greatly improved the feedback on matches and sub-groups. Oyster now highlights the whole match, and all sub-groups (and sub-sub-sub groups etc) much more clearly.