RegExpMiner: Automatically discovering frequently matching regular expressions

Regular expressions (REs) are a very powerful and popular tool to manipu-late string data in a variety of applications. They are used as search templates to look for the occurrences of a given piece of text in a document, or to define how a given piece of text should be formatted in order to be valid (e.g., to check that the value entered in an email field of a Web form is correctly formatted), or even to help solving more complex NLP tasks [NS07]. Their popularity in those various application domains arises from several reasons. First, they are easy to understand and manipulate for common usages, despite their wide ex-pressiveness and power of abstraction. Second, they are natively usable within a large variety of programming languages, hence making them suitable to be integrated into every project addressing text processing tasks. Their usage of-ten relies on a very limited amount of hand-crafted REs. It is indeed dicult to automatically obtain the REs matching with a given set of strings for which no a priori knowledge about their underlying formatting rules is given. Such an automatic discovery of REs would nonetheless o↵er some very interestin