bug#50403: 27.2; calc-grab-region should check rectangle-mark-mode

[Mattias Engdegård]

6 sep. 2021 kl. 11.19 skrev Lars Ingebrigtsen <larsi@gnus.org>:

> I think that sounds reasonable, but I don't use calc much myself.  I've
> added Mattias to the CCs; perhaps he has an opinion here.

Only that he agrees with the previous speakers!

For that matter, in an ideal world the Emacs region/selection would be:

(1) independent of point and mark
(2) of arbitrary shape (linear, rectangular, possibly discontiguous)
(3) represented by an abstract object type in Lisp

and all operations on the region should be able to cope with any shape, with 
useful behaviour for special cases.