On 4 Jul 2008, at 11:23, Chong Yidong wrote:

> David Reitter <david.reitter@gmail.com> writes:
>
>> OK, it seems that (vertical-motion 0) is reliable now with your  
>> patch,
>> but (vertical-motion 1) will sometimes move point to the beginning of
>> the last word in the line (or so), possibly when the visual line is
>> fairly long.  It looks as if it anticipates the word to be wrapped,
>> even though it isn't.
>
> Please provide a detailed recipe.  (If the recipe refers to
> `posn-point', that would be even better.)

It seems to require a variable-width font and a wrapped line that  
reached to the right border.

This is reproducible for me:

Emacs -Q,
(setq word-wrap t)
select variable-width font (I chose Arial 12pt on my OS X machine)
then paste the following text into the *scratch* buffer:

French-Colombian politician Ingrid Betancourt left Bogota bound for  
France and a meeting with President Nicolas Sarkozy one day after her  
jungle rescue from six years in rebel captivity.

NB, this is one sentence that should be without linebreaks.
Resize the frame so that you get line breaks after "France" and  
"jungle". "France" should reach all the way to the right edge of the  
window, as shown in the screenshot.
Place point on the first letter of "Bogota".

M-: (vertical-motion 1) RET

This jumps to the word "France" (the first letter), rather than to  
"and".

Put point back to "Bogota", widen the frame by one character, try  
again.  This time it works: we jump to "and".


I hope that's reproducible in Emacs 23 as well.
I can't find anything wrong with posn-point, but maybe I'm not trying  
the right things.