sig
type 'a t
exception Empty
val create : unit -> 'a Ed_fstack.t
val push : 'a -> 'a Ed_fstack.t -> unit
val pop : 'a Ed_fstack.t -> 'a
val forward : 'a Ed_fstack.t -> 'a
val top : 'a Ed_fstack.t -> 'a
val clear : 'a Ed_fstack.t -> unit
val is_empty : 'a Ed_fstack.t -> bool
val can_forward : 'a Ed_fstack.t -> bool
val length : 'a Ed_fstack.t -> int
val forward_length : 'a Ed_fstack.t -> int
end