(* Identifiers (unique names) *)

type t

val new: string -> t
val new_persistent: string -> t
val name: t -> string
val unique_name: t -> string
val persistent: t -> bool
val equal: t -> t -> bool
        (* Compare identifiers by name. *)      
val same: t -> t -> bool
        (* Compare identifiers by binding location.
           Two identifiers are the same either if they are both
           non-persistent and have been created by the same call to
           [new], or if they are both persistent and have the same
           name. *)
val identify: t -> t -> (unit -> 'a) -> 'a
        (* [identify id1 id2 f] temporarily makes [id1] and [id2] the same
           during the evaluation of [f ()]. *)
val hide: t -> t
        (* Return an identifier with same name as the given identifier,
           but stamp different from any stamp returns by new.
           When put in a 'a tbl, this identifier can only be looked
           up by name. *)

val make_global: t -> unit
val global: t -> bool

val print: t -> unit

type 'a tbl
        (* Association tables from identifiers to type 'a. *)

val empty: 'a tbl
val add: t -> 'a -> 'a tbl -> 'a tbl
val find_same: t -> 'a tbl -> 'a
val find_name: string -> 'a tbl -> 'a

val print_tbl: ('a -> unit) -> 'a tbl -> unit