Benl_frontend
val register_frontend : frontend -> unit
val get_frontend : string -> frontend
val get_selected_frontend : unit -> frontend
val set_selected_frontend : frontend -> unit
val to_string : string -> Benl_types.expr -> string
val to_string_l : string -> Benl_types.expr -> string list
val to_expr_l : string list -> Benl_types.expr
val read_config : ?multi:bool -> Benl_types.source -> Benl_types.config
val read_ben_file : string -> Benl_types.config