      \fitem{rotate}(t:tab, n:int) build a new array which contains the
      elements of \code{t} circularly shifted by \code{n}. If \code{n} is
      positive the element are right shifted, else they are left shifted.
      \begin{lstlisting}
            @rotate([1, 2, 3, 4], -1) == [2, 3, 4, 1]
            @rotate([1, 2, 3, 4], 1) == [4, 1, 2, 3] 
      \end{lstlisting}




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

