% \begin{macro}{\firstchunk}
% \begin{macrocode}
\def\firstchunk{1}
% \end{macrocode}
% In the documentation part `\DocInput` runs under `\MakePercentIgnore`
% (`\catcode`\%=9`), so a `%` is an *ignored* character at any column and an
% indented frame opens a chunk exactly like the column-0 spelling
% (multicol.dtx, latex-lab-block.dtx -- smoke-test issue #71).
% \begin{macrocode}
\def\secondchunk{2}
% \end{macrocode}
% \end{macro}
%
% \begin{macro}{\thirdchunk}
% The indent may be a tab, and the `*` variant is accepted too.
% \begin{macrocode*}
\def\thirdchunk{3}
% \end{macrocode*}
% \end{macro}