(
    (defun partition_inner (matched not-matched F L)
        (if L
            (if (a F (list (f L)))
                (partition_inner (c (f L) matched) not-matched F (r L))
                (partition_inner matched (c (f L) not-matched) F (r L))
            )
            (c matched not-matched)
        )
    )

    (defun partition (F L)
        (partition_inner () () F L)
    )
)