---------------------------------------------------------------------------
   Assign a(i)
---------------------------------------------------------------------------
   Form:
   a = subsasgn( a, s, b )
---------------------------------------------------------------------------

   ------
   Inputs
   ------
   a           (:)   Object of class acstate
   s           (:)   Structure

   -------
   Outputs
   -------
   b           (1,1)  Scalar

---------------------------------------------------------------------------