Compatibility of datetime data type about toml-f

[milancurcic]

It could be useful to include adapters to other datetimes, perhaps under a separate repo, perhaps toml-f/toml-datetime-adapters or similar. I think you should keep the main toml-f library clean and not pull in other datetime implementations. If and when there is ever an ubiquitous datetime implementation in Fortran, then you could just use that in the main toml-f library.

But showing how to do this in the toml-f docs would be a good first step IMO. For datetime-fortran, something like this (I didn't test the code, only typed it here)?

module tomlf_datetime_adapters
  use tomlf_datetime, only: toml_datetime
  use datetime_module, only: datetime
  implicit none
contains
  elemental type(datetime) function toml_datetime_to_datetime_fortran(d) result(res)
    type(toml_datetime), intent(in) :: d
    res = datetime( &
      year=d % date % year, &
      month=d % date % month, &
      day=d % date % day, &
      hour=d % time % hour, &
      minute=d % time % minute, &
      second=d % time % second, &
      millisecond=d % time % msec, &
      tz=timezone_offset_from_timezone_name(d % time % zone) ! not implemented
    )
  end function toml_datetime_to_datetime_fortran
end module tomlf_datetime_adapters

[milancurcic]

I only now saw #103, looks good.