Re: CSS character width unit missing: an oversight, methinks?

Thanks to people who replied to my first posting. Maybe I am in above my
head,
but I would like to offer the following simple suggestion:

  Introduce a parameterized unit called owidth (o for "outer").  It
  has the syntax owidth('T'), where T is any string of characters.  It's
  meaning for an element E is the width of an imagined box containing
  T; the imagined box is typeset in the same context as that of the
  E.

I hope this semantics is sound.  This proposal is very flexible and
contains no arbitrary decisions as Bert hinted any canonized unit
would entail ("width of what" for proportional-width fonts).

I could now easily---even with a fixed-width font---typeset
mathematics-kind-of-stuff like

(  A = B or
   C = D )

where the exercise is to get the A to line up with the C, and where I
would like to typeset each line in its own div box (so that if a
line-wrap around occurs, then the display doesn't get too mixed up).

I would write something like

<div style="margin-left: owidth('( ');
            text-indent: -owidth('( ');">( A = B or
</div>
<div style="margin-left: owidth('( ');">C=D )</div>

/Nils