title: Carets in Regular Expressions
body: <p>Specifically when does <code>^</code> mean "match start" and when does it mean "not the following" in regular expressions? </p>
  
  <p>From the Wikipedia article and other references, I've concluded it means the former at the start and the latter when used with brackets, but how does the program handle the case where the caret is at the start and at a bracket? What does, say, <code>^[b-d]t$</code> match? </p>