      \fitem{scan}(f:function, t:tab) returns the tab %%
      \code{[ t[0], f(t[0],t[1]), f(f(t[0], t[1]),t[2]), ...]}. For
      example, the tab of the partial sums of the integers between
      \code{0} (included) and \code{10} (excluded) is computed by the
      expression:
      \begin{lstlisting}
            @scan(@+, [$x | $x in (10)])  -> [0,1,3,6,10,15,21,28,36,45]
      \end{lstlisting}



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

