I want to typeset a multiplication table, where there will be a horizontal
line after the first row, and a vertical line after the first column.  In
LaTeX, I can use:

\[
\begin{array}{c|ccccccc}
  \times&0&1&2&3&4&5&6\\
  \hline
  0&0&0&0&0&0&0&0\\
  1&0&1&2&3&4&5&6\\
  2&0&2&4&6&1&3&5\\
  3&0&3&6&2&5&1&4\\
  4&0&4&1&5&2&6&3\\
  5&0&5&3&1&6&4&2\\
  6&0&6&5&4&3&2&1
\end{array}
\]

What is the canonical way of including lines in a mathematical array in
ConTeXt?

Thanks,
Alasdair