The first time I ever encountered a regular expression was many years ago now, but I still remember my first thoughts on it: What is this string-like thing? I don’t want to touch it, it looks scary. I ...

How do you find out if a user has entered a valid email address? Do you check for an at-sign, or is it more complicated? For many developers the answer is a regular expression, a little bit of code ...

The Internet Engineering Task Force (IETF) document, RFC 3696, “Application Techniques for Checking and Transformation of Names” by John Klensin, gives several valid e-mail addresses that are rejected ...