Simple math with regular expressions?
Historical article · Originally published November 8, 2004; technical details may be outdated.
A friend of mine (Ariel) made the bold claim that it is possible to write a regular expression (in today's languages such as .Net) that checks simple mathematical functions, for example if a number is divisible by 3. I looked and looked and asked and checked and could find no mention of this. I'm not talking theoretically; I'm looking for an example that shows me this. Can you provide one?