      \fitem{+}(\vValue, \vValue), \vListable: prefix form of the infix
      \code{+} binary operator: \code{@+(x, y)} $\equiv$ \code{x+y}. The
      functional form of the operator is useful as an argument of
      a high-order function as in \code{@reduce(@+, v)} which sums up
      all the elements of the tab \code{v}.
      
      The addition of an \code{int} and a \code{float} returns a
      float. 

      The addition of two \code{string} corresponds to the concatenation
      of the arguments. The addition of a string and any other value
      convert this value into its string representation before the
      concatenation. 
