intuition.
eapply evalDet_repeat_steps_more_inv_h; eauto.
Qed.

(* The result of evaluation is decidable. *)
Lemma evalDet_steps_dec : forall (A : Set)(c : Comp A),
well_formed_comp c ->
forall s,
(exists a s', evalDet_steps (cs_more c s) (cs_done a s')) \/
(evalDet_steps (cs_more c s) (@cs_eof A)).