`functor (I : IncrementalEngine.EVERYTHING)
(User : sig
val print : string -> unit
val print_symbol : I.xsymbol -> unit
val print_element : (I.element -> unit) option
end)
->
sig
val print_symbols : I.xsymbol list -> unit
val print_element_as_symbol : I.element -> unit
val print_stack : 'a I.env -> unit
val print_item : I.item -> unit
val print_production : I.production -> unit
val print_current_state : 'a I.env -> unit
val print_env : 'a I.env -> unit
end`