module type Key =sig
..end
type 'a
key
val create_key : string -> 'a key
val eq_type : 'a key -> 'b key -> ('a, 'b) Structure.eq option
val print : 'a key Pretty_utils.formatter
val compare : 'a key -> 'b key -> int
val equal : 'a key -> 'b key -> bool
val hash : 'a key -> int
val tag : 'a key -> int