ocaml-containers/src/core/CCOrd.mli
2015-12-29 17:19:43 +01:00

55 lines
1.5 KiB
OCaml

(* This file is free software, part of containers. See file "license" for more details. *)
(** {1 Comparisons} *)
type 'a t = 'a -> 'a -> int
(** Comparison (total ordering) between two elements, that returns an int *)
val compare : 'a t
(** Polymorphic "magic" comparison *)
val opp : 'a t -> 'a t
(** Opposite order *)
val equiv : int -> int -> bool
(** Returns [true] iff the two comparison results are the same *)
val int_ : int t
val string_ : string t
val bool_ : bool t
val float_ : float t
(** {2 Lexicographic Combination} *)
val (<?>) : int -> ('a t * 'a * 'a) -> int
(** [c1 @@? (ord, x, y)] returns the same as [c1] if [c1] is not [0];
otherwise it uses [ord] to compare the two values [x] and [y],
of type ['a].
Example:
{[CCInt.compare 1 3
<?> (String.compare, "a", "b")
<?> (CCBool.compare, true, false)]}
*)
val option : 'a t -> 'a option t
(** Comparison of optional values. [None] is smaller than any [Some _].
@since 0.15 *)
val pair : 'a t -> 'b t -> ('a * 'b) t
val triple : 'a t -> 'b t -> 'c t -> ('a * 'b * 'c) t
val list_ : 'a t -> 'a list t
(** Lexicographic combination on lists *)
val array_ : 'a t -> 'a array t
val map : ('a -> 'b) -> 'b t -> 'a t
(** [map f ord] is the comparison function that, given objects [x] and [y],
projects [x] and [y] using [f] (e.g. using a record field) and then
compares those projections with [ord].
Example:
[map fst CCInt.compare] compares values of type [(int * 'a)] by their
first component. *)