Support for submodules ?

[John Chludzinski]

I'm starting a potentially large Fortran project and doing some
gfortran inventory.  Just noticed "submodules", apparently a Fortran
analog to Ada's "package body".

Went to the Fortran Wiki for an example:

module points
  type :: point
     real :: x, y
  end type point

  interface
     module function point_dist(a, b) result(distance)
       type(point), intent(in) :: a, b
       real :: distance
     end function point_dist
  end interface
end module points

submodule (points) points_a
contains
  module function point_dist(a, b) result(distance)
    type(point), intent(in) :: a, b
    real :: distance
    distance = sqrt((a%x - b%x)**2 + (a%y - b%y)**2)
  end function point_dist
end submodule points_a

Tried compiling it and got:

$ gfortran -c t.f95
t.f95:7.5:

     module function point_dist(a, b) result(distance)
     1
Error: Unclassifiable statement at (1)
t.f95:8.38:

       type(point), intent(in) :: a, b
                                      1
Error: Unexpected data declaration statement in INTERFACE block at (1)
t.f95:9.23:

       real :: distance
                       1
Error: Unexpected data declaration statement in INTERFACE block at (1)
t.f95:10.8:

     end function point_dist
        1
Error: Expecting END INTERFACE statement at (1)
t.f95:14:

submodule (points) points_a
1
Error: Unclassifiable statement at (1)
t.f95:16.2:

  module function point_dist(a, b) result(distance)
  1
Error: Unclassifiable statement at (1)
t.f95:17.15:

    type(point), intent(in) :: a, b
               1
Error: Derived type 'point' at (1) is being used before it is defined
t.f95:18.20:

    real :: distance
                    1
Error: Unexpected data declaration statement in CONTAINS section at (1)
t.f95:19.22:

    distance = sqrt((a%x - b%x)**2 + (a%y - b%y)**2)
                      1
Error: Expected a right parenthesis in expression at (1)
t.f95:20.5:

  end function point_dist
     1
Error: Expecting END PROGRAM statement at (1)
t.f95:21.3:

end submodule points_a
   1
Error: Expecting END PROGRAM statement at (1)
Error: Unexpected end of file in 't.f95'


Is there support for this in the upcoming 4.8?

---John