(* simple_tac = Repeat(OrElse(conj_hyp_tac(), conj_tac(), assumption_tac())) *) theorem T2 (A B : Bool) : A /\ B → B /\ A := fun H : A /\ B, let H1 : A := _, H2 : B := _, main : B /\ A := _ in main. simple_tac. done. simple2_tac. done. simple_tac. done. print "echo command after failure"