`sig
type t
val ( >=. ) : Robustly_comparable.S.t -> Robustly_comparable.S.t -> bool
val ( <=. ) : Robustly_comparable.S.t -> Robustly_comparable.S.t -> bool
val ( =. ) : Robustly_comparable.S.t -> Robustly_comparable.S.t -> bool
val ( >. ) : Robustly_comparable.S.t -> Robustly_comparable.S.t -> bool
val ( <. ) : Robustly_comparable.S.t -> Robustly_comparable.S.t -> bool
val ( <>. ) : Robustly_comparable.S.t -> Robustly_comparable.S.t -> bool
val robustly_compare :
Robustly_comparable.S.t -> Robustly_comparable.S.t -> int
end`