Re: term.el and undo

[Mark Plaksin <happy@mcplaksin.org>]

Florian Weimer <fw@deneb.enyo.de> writes:

> * David Kastrup:
>
>> However, since the whole point of term is to provide an
>> ncurses-capable terminal, and since undo or any other output or cursor
>> movement operation not initiated from the device writing into the
>> pseudotty would lead to a discrepancy between the screen contents and
>> the application's expectations, _any_ editing by the user including
>> undo would seem completely pointless.
>
> Minor nitpick: In *line* *mode*, undo does make sense, because the
> application doesn't see any data before the user presses RET.  (Line
> mode is the default mode, and typically it supports limited line
> editing via ^H, ^W and ^U.)

Right but it only makes sense *on the current command-line*.  Undoing
anything beyond that will make the point move to some random place in the
window where some prior insert happened.

Say you typed ls at the top of the window and the output took up half the
window.  The point is in the middle of the window.  Then while typing your
next command you delete some text and want to undo the deletion.  That
works fine unless you undo again--that will make the point move to the top
of the buffer which probably isn't what you want.