In order to implement Emacs-style mini-buffer C-g handling, such that if there is an active (selected) region, C-g clears/deactivates the region, and otherwise cancels the read from the mini-buffer, it would be useful for there to be a function which indicates whether there is an active mark. It might also be useful for there to be a function to return the substring which the active region contains, and a function which indicates the position of the mark.
-- Jeremy Maitin-Shepard
