Re: region-active-p

["Stephen J. Turnbull" <stephen@xemacs.org>]

Richard Stallman writes:

 > When commands in XEmacs call [region-active-p], do they also test
 > for a nonempty region?  Or do they operate on the region
 > when it is empty?

Core commands defined in Lisp don't test (at least not within 3 lines,
checked with grep -3), but they're generally wrappers for functions
defined in C that do test (eg, the casefilling commands).

 > I don't see any need for region-exists-p
 > unless we want it specifically to run code in Emacs
 > which was written for XEmacs.

The use-case in XEmacs is that some code wishes to operate on the
region regardless of whether it is active.  All examples in XEmacs
core code are used to determine whether a menu item or dialog button
is active; I presume that the corresponding functions query the user
if the region exists but is inactive, and simply executes if the
region is active.  I don't know if there are any important uses.