Numeric Range Question Type
CAT-SOOP 1.0 had a question type where users were asked to enter an expression whose answer was a range of numbers. For example,
[0,3)U(4,7] was a well-formed input representing a range from 0 (inclusive) to 3 (exclusive) and from 4 (exclusive) and 7 (inclusive).
I've had a couple of requests to bring this back. CAT-SOOP has changed a lot since then, but I think it's possible that it would be a relatively straightforward port of the code from 1.0.