(** [replace lst tag newval]
  Replace or add an entry to an alist. *)
val replace : ('a * 'b) list -> 'a -> 'b -> ('a * 'b) list

(** Merge a list of alists, with the first occurrence of each
  attribute taking precedence. *)
val merge : ('a * 'b) list list -> ('a * 'b) list

(** Strip any attributes present in a out of b *)
val diff : ('a * 'b) list -> ('a * 'c) list -> ('a * 'c) list

(** Add a pair to an alist, but don't replace current value. *)
val no_replace : ('a * 'b) list -> 'a -> 'b -> ('a * 'b) list

(** Return a list of all values for an attribute. *)
val assoc_all : 'a -> ('a * 'b) list -> 'b list

val assoc_opt : 'a -> ('a * 'b) list -> 'b option

val invert : ('a * 'b) list -> ('b * 'a) list

(** List2.enumerate *)
val enumerate : 'a list -> (int * 'a) list

val sort_car : ('a -> 'a -> int) -> ('a * 'b) list -> ('a * 'b) list

val sort_cdr : ('a -> 'a -> int) -> ('b * 'a) list -> ('b * 'a) list

(** List.assoc *)
val assoc : 'a -> ('a * 'b) list -> 'b

(** List.remove_assoc *)
val remove_assoc : 'a -> ('a * 'b) list -> ('a * 'b) list

(** List.split *)
val split : ('a * 'b) list -> 'a list * 'b list