When is a issue too complex for a regular expression?

Question

Please don\'t answer the obvious, but what are the limit signs that tell us a problem should not be solved using regular expressions?

For example: Why is a complete emai

Answer 1

A few things to look out for:

1. beginning and ending tag detection -- matched pairing
2. recursion
3. needing to go backwards (though you can reverse the string, but that's a hack)

regexes, as much as I love them, aren't good at those three things. And remember, keep it simple! If you're trying to build a regex that does "everything", then you're probably doing it wrong.