      \fitem{insert}(m:map, k:val, v:val), \vImpure: inserts ``in place''
      a new entry \code{k} with value \code{v} in the map \code{m}. See
      \acode{add_pair}.  Notice that the form \code{@insert "file"} is
      also used to include a file at parsing time.



      %%% -------------------------------------------------------

