On Thu, 15 Jul 2010 02:33:03 -0600, Peter Rolf <indiego@gmx.net> wrote:

> has to do with the way the column width is calculated. the combined
> entries (2+3,4+5) in row one can only influence (increase) the total
> width of the involved columns, but they can not give an answer to the
> question how wide the single columns should be.
> in the end you need a linear system of equations (and metapost) to solve
> this. and there is also no guarantee that it is solvable in all (more
> complex) cases.
> col2=col3; col4=col5;
> col2+col3= ....;
> col4+col5= ....;

Ok... But it seems inescapable that this is a bug in some sense. If we  
simplify things, compare

======================================
\starttext
\starttables[|c|c|]
\HL
\VL \Use{2}[c]{B} \VL\AR
\HL
\VL  B \VL B                \VL\AR
\HL
\stoptables
\blank
\starttables[|c|c|]
\HL
\VL \Use{2}[c]{BBBBBBB} \VL\AR
\HL
\VL  B \VL B                \VL\AR
\HL
\stoptables
\stoptext
====================================

Your mathematical explanation makes sense, but to a new user I doubt one  
could convince him/her that the second table is a feature and not a bug.  
But I understand that the challenge may be complicated.

Till then, we need a simple workaround if that's possible.

> also: i can't imagine how a user interface for this should look like.

\setuptables[spanalign=balance]

or something....

>>> maybe like this...
>>
>> That's a great workaround, and I appreciate it. But what about new
>> users? There has got to be a more elegant solution to this seemingly
>> simple table. Row two just does not look right...
>>
> true, but this is font related. you can see this by using
> \ruledhbox{ʿAlī}. you have to add some manual kerning (\kern-0.??em ...)
> then.

I don't see the font-relatedness, even with \ruledhbox... Hence the above  
simple test case.

As we work to bring ConTeXt to a wider audience -- I'm currently involved  
with such efforts, we should keep track of outwardly "simple" cases like  
the above ...

Thanks again and

Best wishes
Idris
-- 
Professor Idris Samawi Hamid, Editor-in-Chief
International Journal of Shīʿī Studies
Department of Philosophy
Colorado State University
Fort Collins, CO 80523