Re: make-field suggestion

[Jerry James <james@xemacs.org>]

Stefan <monnier@iro.umontreal.ca>, on 31 Aug 2004 at 22:48:14 -0400 you
wrote:
>> make-overlay docstring in that case.  Hmmmm.... so is it true that
>> overlays are neither front- nor rear-sticky by default?  But the text
>
> No, AFAIK they're front-sticky ("not front-advance") and
> rear-non-sticky ("not rear-advance").

I'm misunderstanding something then.  The docstring for make-overlay
says:

  Create a new overlay with range BEG to END in BUFFER.
  If omitted, BUFFER defaults to the current buffer.
  BEG and END may be integers or markers.
  The fourth arg FRONT-ADVANCE, if non-nil, makes the
  front delimiter advance when text is inserted there.
  The fifth arg REAR-ADVANCE, if non-nil, makes the
  rear delimiter advance when text is inserted there.

Since front-advance and rear-advance are both optional, they default to
nil, no?  Which means that (make-overlay 10 20) makes an overlay that is
front-non-sticky and rear-non-sticky.  The code in buffer.c seems to
bear this out:

  if (!NILP (front_advance))
    XMARKER (beg)->insertion_type = 1;
  if (!NILP (rear_advance))
    XMARKER (end)->insertion_type = 1;

Where have I gone wrong?  Is there some other function I should be
looking at instead of make-overlay?

Thanks,
-- 
Jerry James
http://www.ittc.ku.edu/~james/