Or are we talking TB in the sense that a character keeps executing the last order given, such as a thief in the rear of the party continuously firing arrows at the nearest target until ordered to do something different?
I don't know what you mean by TB, but if a character in the party can keep doing anything, it isn't TB. In fact, I don't think there is any such thing as an auto attack in turn based systems. Just think of how DOS operates to get an idea of TB. Have you played DOS1 and/or 2?