Comparable extends Base.Comparable
and provides functions for
comparing like types.
Usage example:
module Foo = struct
module T = struct
type t = ... [@@deriving compare, sexp]
end
include T
include Comparable.Make (T)
end
Then include Comparable.S
in the signature (see Comparable_intf for an
example).
To add an Infix
submodule:
module C = Comparable.Make (T)
include C
module Infix = (C : Comparable.Infix with type t := t)
Common pattern: Define a module O
with a restricted signature. It aims to be
(locally) opened to bring useful operators into scope without shadowing unexpected
variable names. E.g. in the Date
module:
module O = struct
include (C : Comparable.Infix with type t := t)
let to_string t = ..
end
Opening Date
would shadow now
, but opening Date.O
doesn't:
let now = .. in
let someday = .. in
Date.O.(now > someday)
module type Infix = Core_kernel__.Comparable_intf.Infix
module type S_plain = Core_kernel__.Comparable_intf.S_plain
module type S = Core_kernel__.Comparable_intf.S
module type S_binable = Core_kernel__.Comparable_intf.S_binable
module type S_common = Core_kernel__.Comparable_intf.S_common
module type Validate = Core_kernel__.Comparable_intf.Validate
module type With_zero = Core_kernel__.Comparable_intf.With_zero
val lexicographic : ('a ‑> 'a ‑> int) list ‑> 'a ‑> 'a ‑> int
lexicographic cmps x y
compares x
and y
lexicographically using functions in the
list cmps
.
val lift : ('a ‑> 'a ‑> 'int_or_bool) ‑> f:('b ‑> 'a) ‑> 'b ‑> 'b ‑> 'int_or_bool
lift cmp ~f x y
compares x
and y
by comparing f x
and f y
via cmp
.
The Comparable Make functor family allows users to choose among the following attributes:
*_using_comparator
or not*_binable
or not*_plain
or notThus there are functors like Make_plain
or Make_binable_using_comparator
, etc.
module Make_plain : functor (T : sig ... end) -> S_plain with type t := T.t
module Make_plain_using_comparator : functor (T : sig ... end) -> S_plain with type t := T.t with type comparator_witness := T.comparator_witness
module Make_using_comparator : functor (T : sig ... end) -> S with type t := T.t with type comparator_witness := T.comparator_witness
module Make_binable : functor (T : sig ... end) -> S_binable with type t := T.t
module Make_binable_using_comparator : functor (T : sig ... end) -> S_binable with type t := T.t with type comparator_witness := T.comparator_witness
module Extend : functor (M : Base.Comparable.S) -> functor (X : sig ... end) -> S with type t := M.t with type comparator_witness := M.comparator_witness
module Extend_binable : functor (M : Base.Comparable.S) -> functor (X : sig ... end) -> S_binable with type t := M.t with type comparator_witness := M.comparator_witness
module Map_and_set_binable : functor (T : sig ... end) -> Map_and_set_binable with type t := T.t
module Map_and_set_binable_using_comparator : functor (T : sig ... end) -> Map_and_set_binable with type t := T.t with type comparator_witness := T.comparator_witness
module Validate_with_zero : functor (T : sig ... end) -> sig ... end
The following module types and functors may be used to define stable modules:
module Stable : sig ... end