Diagonal separator in table corner in ConTeXt

Question

How can one create a diagonal separator in a table corner in ConTeXt (like the package slashbox for LaTeX)?

Answer 1

Here is a solution based on natural tables:

\startuseMPgraphic{DiagonalRule}
draw (0,OverlayHeight) -- (OverlayWidth,0);
clip currentpicture to OverlayBox; % otherwise the rule overlaps the table frame
\stopuseMPgraphic

\defineoverlay
  [DiagRule]
  [\useMPgraphic{DiagonalRule}]

\setupTABLE [1] [1] [background=DiagRule]

\starttext
\bTABLE
\bTR \bTD   \eTD   \bTD col   \eTD \eTR
\bTR \bTD row \eTD \bTD value \eTD \eTR
\eTABLE
\stoptext

The nice thing about natural tables is that the background of a cell can be just about anything. In this case, I am using a simple metapost graphic that draws a diagonal line.