How to use rowcount, rownum, colcount, and colnum variables in hooks

[kalekje]

I would like to use these variables to create a custom TableCommand. How do I access these variables? Please see MWE below.

\documentclass{scrartcl}
\usepackage{luacode}
\usepackage{tabularray}

\UseTblrLibrary{hook}



\AddToHook{tabularray/cell/before}{-}
\AddToHook{tabularray/cell/after}{-}

\begin{document}

\begin{tblr}{|l|l|l|}
  rownum, colnum & rownum, colnum & rownum, colnum\\
\end{tblr}

\end{document}