title: using regex to validate date
body: <p>All the examples I found are checking if the string follows a certain pattern and is digit, for example <code>"\d{4}-\d{2}-\d{2}"</code>. I want to check if the date is later than a given date, for example, to check if the date follows pattern "yyyy-mm-dd" and is later than "2009-03-01". How to achieve that?</p>