intuition.
eapply evalDet_steps_skipn_h; eauto.
Qed.

Lemma evalDet_repeat_steps_dec : forall (s : Blist)(A : Set)(c : Comp A)(P : A -> bool),
(exists a, In a (getSupport c) /\ P a = true) ->
(forall s', (exists a s'', evalDet_steps (cs_more c s') (cs_done a s'')) \/ evalDet_steps (cs_more c s') (@cs_eof A)) ->
exists y, evalDet_repeat_steps P (cs_more c s) y.