On Thu, 3 May 2012, Wolfgang Schuster wrote:

> You assume \definelinenumbering has a second argument for the settings but this isn’t the case

D'oh.

> and you need \setuplinenumbering to set them.

I also needed to change \setvalue to \setevalue in the example, and add an 
\expanded to get it to work.

\definenamespace
      [whatever]
      [
        type=module,
        name=whatever,
        command=yes,
        setup=yes,
        parent=whatever,
      ]

\appendtoks
      \definelinenumbering
            [\currentwhatever]%
      \expanded{\setuplinenumbering
            [\currentwhatever]
            [
              color=\whateverparameter{numbercolor},
              style=\whateverparameter{numberstyle},
            ]}%

\setevalue{start\currentwhatever}{\dostartwhatever[\currentwhatever]}%
      \setevalue{stop\currentwhatever}{\dostopwhatever}%
\to\everydefinewhatever

% For illustration. The actual macro is more complicated.
\def\dostartwhatever[#1]%
      {\startlinenumbering[#1]}

\def\dostopwhatever
      {\stoplinenumbering}

%%%%

\definewhatever[testing][numbercolor=red,numberstyle=bold]

\starttext
\starttesting
    \input knuth
\stoptesting
\stoptext

Thanks,
Aditya