val seq: tactics: tactic list -> tactic (** "folding" of then_ *)
val repeat_tactic: tactic: tactic -> tactic
val do_tactic: n: int -> tactic: tactic -> tactic
val try_tactic: tactic: tactic -> tactic
val seq: tactics: tactic list -> tactic (** "folding" of then_ *)
val repeat_tactic: tactic: tactic -> tactic
val do_tactic: n: int -> tactic: tactic -> tactic
val try_tactic: tactic: tactic -> tactic