add_sources_from_dir Subroutine

subroutine add_sources_from_dir(sources,directory,scope,with_executables,with_f_ext,recurse,error)
    !> List of `[[srcfile_t]]` objects to append to. Allocated if not allocated
    type(srcfile_t), allocatable, intent(inout), target :: sources(:)
    !> Directory in which to search for source files
    character(*), intent(in) :: directory
    !> Scope to apply to the discovered sources, see [[fpm_model]] for enumeration
    integer, intent(in) :: scope
    !> Executable sources (fortran `program`s) are ignored unless `with_executables=.true.`
    logical, intent(in), optional :: with_executables
    !> Additional user-defined (preprocessor) extensions that should be treated as Fortran sources
    type(string_t), intent(in), optional :: with_f_ext(:)
    !> Whether to recursively search subdirectories, default is `.true.`
    logical, intent(in), optional :: recurse
    !> Error handling
    type(error_t), allocatable, intent(out) :: error

    integer :: i
    logical, allocatable :: is_source(:), exclude_source(:)
    logical :: recurse_
    type(string_t), allocatable :: file_names(:)
    type(string_t), allocatable :: src_file_names(:),f_ext(:)
    type(string_t), allocatable :: existing_src_files(:)
    type(srcfile_t), allocatable :: dir_sources(:)

    recurse_ = .true.
    if (present(recurse)) recurse_ = recurse
    ! Scan directory for sources
    call list_files(directory, file_names,recurse=recurse_)

    if (allocated(sources)) then
        allocate(existing_src_files(size(sources)))
        do i=1,size(sources)
            existing_src_files(i)%s = canon_path(sources(i)%file_name)
        end do
    else
        allocate(existing_src_files(0))
    end if

    ! Get legal fortran suffixes
    call list_fortran_suffixes(f_ext,with_f_ext)

    is_source = [(.not.(is_hidden_file(basename(file_names(i)%s))) .and. &
                 .not.(canon_path(file_names(i)%s) .in. existing_src_files) .and. &
                 (str_ends_with(lower(file_names(i)%s), f_ext) .or. &
                 str_ends_with(lower(file_names(i)%s), c_suffixes) ),i=1,size(file_names))]


    src_file_names = pack(file_names,is_source)

    allocate(dir_sources(size(src_file_names)))
    allocate(exclude_source(size(src_file_names)))

    do i = 1, size(src_file_names)

        dir_sources(i) = parse_source(src_file_names(i)%s,with_f_ext,error)
        if (allocated(error)) return

        dir_sources(i)%unit_scope = scope
        allocate(dir_sources(i)%link_libraries(0))

        ! Exclude executables unless specified otherwise
        exclude_source(i) = (dir_sources(i)%unit_type == FPM_UNIT_PROGRAM)
        if (dir_sources(i)%unit_type == FPM_UNIT_PROGRAM .and. &
            & present(with_executables)) then
            if (with_executables) then

                exclude_source(i) = .false.

            end if
        end if

    end do

    if (.not.allocated(sources)) then
        sources = pack(dir_sources,.not.exclude_source)
    else
        sources = [sources, pack(dir_sources,.not.exclude_source)]
    end if

end subroutine add_sources_from_dir