bug#12723: 24.2; Improvement: changing text rectangle kill/past and its integration with the kill-ring

[Stefan Monnier <monnier@iro.umontreal.ca>]

> How would such a rectangular highlighting behave when some of the text
> in the region is R2L and some L2R?  Will it select text in visual
> order or in logical (buffer) order?

The rectangle operations do not currently pay attention to this (they
work on logical order) and the highlighting would do the same since the
highlighting is there to make visible what the rectangle operations
would/will do.

> Anyway, doing this kind of stuff in Lisp is not trivial even if we
> disregard the bidirectional text issue, because variable-size fonts,
> double-width characters, composed characters, display strings, and
> other display atrocities complicate the 1:1 relation between buffer
> text and what's on the glass.

Similarly, variable-width fonts and stuff would not require more work in
the highlighting than in kill-rectangle.
I'm not saying they're not relevant, but as long as kill-rectangle
doesn't take them into account, the highlighting shouldn't either.


        Stefan