[emacs-bidi] Incorrect cursor positioning for BN characters at EOL

[Larry Denenberg]

Start with an empty buffer and set bidi-display-reordering non-nil.
(BTW, it would be nice for this variable's doc to start with an asterisk
so you could set it with M-x set-variable.)

Now enter text on the first line, plus a line ending in a backspace
(which displays as ^?), followed by other lines.  E.g., enter this:

  hello RET RET RET RET RET abc RET def ^P ^E ^Q <delete>

[Digression:  Why does the ^P here put the cursor after the "d" rather
than after the "f", as I expect?  This is an Aquamacs, not bidi, thing.]

At this point you expect the cursor to be just after the ^?, but it has
jumped to the end of the first line of the buffer.  It's not really
there, it just displays there whenever it's immediately after the ^?, as
you can prove by moving the cursor around.  It also displays at the end
of the top line if it's just before the ^?, but only if you got there
from just after it, not if you sneak up from in front.

Other weird things happen if you can't see the top of the buffer, or if
you try to insert newlines when the cursor is mis-displayed, and so
forth, but I'll let you find those for yourself if it's important.

As the subject line says, presumably the salient point is that ^? has
bidi-class BN.  But that's really an assumption on my part.

/Larry Denenberg
address@hidden
http://larry.denenberg.com/