schema_add_external_group Subroutine

   subroutine schema_add_external_group(this, name)
      !! Register a group name the schema knows exists but does NOT
      !! validate (its body is skipped silently).
      class(nml_schema_t), intent(inout) :: this
      character(len=*), intent(in) :: name
      character(len=:), allocatable :: tmp(:)
      integer :: n, newlen, i

      if (.not. allocated(this%external_names)) allocate (character(len=0) :: this%external_names(0))
      n = size(this%external_names)
      newlen = max(len(this%external_names), len(name))
      allocate (character(len=newlen) :: tmp(n + 1))
      do i = 1, n
         tmp(i) = this%external_names(i)
      end do
      tmp(n + 1) = name
      call move_alloc(tmp, this%external_names)
   end subroutine schema_add_external_group