subroutine set_plot (plot, data, do_set)

  use cesrv_struct
  use cesrv_interface

  implicit none

  type (p2_plot_struct), target :: plot
  type (d2_data_struct) :: data

  character(20) where
  logical, optional :: do_set

  !

  if (.not. logic_option (.false., do_set) .and. logic%plot_locked) return

  ! store current plot info into old data struct and point to new data struct

  if (associated(plot%d2)) then
    plot%d2%p2 = plot
    plot%d2%p2%plot1%p2 => plot%d2%p2
    plot%d2%p2%plot2%p2 => plot%d2%p2
    plot%d2%p2%plot3%p2 => plot%d2%p2
  endif

  where = plot%where
  plot = data%p2
  plot%where = where

  plot%plot1%p2 => plot
  plot%plot2%p2 => plot
  plot%plot3%p2 => plot

end subroutine