Module Ascii_as_OT <: UsualOrderedType.
Definition t := ascii.
Definition eq := @eq ascii.
Definition eq_refl := @eq_refl t.
Definition eq_sym := @eq_sym t.
Definition eq_trans := @eq_trans t.
Definition cmp : ascii -> ascii -> comparison := Ascii.compare.

Lemma cmp_antisym (a b : ascii):
cmp a b = CompOpp (cmp b a).