Shiv Shankar Dayal schrieb am 27.12.2023 um 13:31:

>     What do you expect here to pass as argument to the oldfact command?
>
> I will pass something like n, 5, 10 etc.

A simple alternative to tikz is the usage of \framed.

\define[1]\oldfact
   {\inmframed[frame=off,strut=no,leftframe=on,bottomframe=on]{#1}}

\starttext

\m{\oldfact{n}}

\stoptext

Wolfgang