Mappable.Extend1
Extend1
implements Extensions1 for an arity-1 mappable container.
module S : Mappable_types.S1_container
Extensions1
includes the container extensions from Container_exts
, as they work with any arity-1 container.
include Container_exts_types.S1 with type 'a t := 'a S.t
include Container_exts_types.Generic
with type ('a, 'phantom) t := 'a S.t
and type 'a elt := 'a
Generic
refers to the container type as 'a t
, and the element type as 'a elt
; substitute t
/elt
(arity-0) or 'a t
/'a
(arity-1) accordingly below.
include Generic_types.Generic
with type ('a, 'phantom) t := 'a S.t
with type 'a elt := 'a
The following functions help in checking whether a container has a particular, commonly-required number of elements (zero or one, one, two, and so on).
val at_most_one : 'a S.t -> 'a Base.option Base.Or_error.t
at_most_one xs
returns Ok None
if xs
is empty; Ok Some(x)
if it contains only x
; and an error otherwise.
Examples (using an extended version of List):
(* ok None *)
List.at_most_one []
(* ok (Some 1) *)
List.at_most_one [1]
(* error -- too many *)
List.at_most_one [1; 2]
val one : 'a S.t -> 'a Base.Or_error.t
one xs
returns Ok x
if xs
contains only x
, and an error otherwise.
Examples (using an extended version of List):
(* error -- not enough *)
List.one []
(* ok 1 *)
List.one [1]
(* error -- too many *)
List.one [1; 2]
val two : 'a S.t -> ('a * 'a) Base.Or_error.t
two xs
returns Ok (x, y)
if xs
is a list containing only x
and y
in that order, and an error otherwise.
Examples (using an extended version of List):
(* error -- not enough *)
List.two []
(* error -- not enough *)
List.two [1]
(* ok (1, 2) *)
List.two [1; 2]
(* error -- too many *)
List.two [1; 2; 3]
val max_measure :
measure:('a -> Base.int) ->
?default:Base.int ->
'a S.t ->
Base.int
max_measure ~measure ~default xs
measures each item in xs
according to measure
, and returns the highest measure reported. If xs
is empty, return default
if given, and 0
otherwise.
Predicate extensions are available on all arity-1 containers, provided that we fix the element type parameter to 'a -> bool
.
include Container_exts_types.Generic_predicate
with type ('a, 'phantom) t := ('a -> Base.bool) S.t
and type 'a item := 'a
val any : 'a -> predicates:('a -> Base.bool) S.t -> Base.bool
any x ~predicates
tests x
against predicates
until one returns true
, in which case it returns true
; or all return false
, in which case it returns false
.
val all : 'a -> predicates:('a -> Base.bool) S.t -> Base.bool
any x ~predicates
tests x
against predicates
until one returns false
, in which case it returns false
; or all return true
, in which case it returns true
.
val none : 'a -> predicates:('a -> Base.bool) S.t -> Base.bool
none x ~predicates
is the same as any x
with all predicates in predicates
negated. It tests x
against predicates
until one returns true
, in which case it returns false
; or all return false
, in which case it returns true
.
right_pad ~padding xs
pads every list in xs with padding
, ensuring all lists have equal length.
Example:
right_pad ~padding:6
[ [0; 8; 0; 0] (* [ [ 0; 8; 0; 0; 6 ] *)
; [9; 9; 9] (* ; [ 9; 9; 9; 6; 6 ] *)
; [8; 8; 1; 9; 9] (* ; [ 8; 8; 1; 9; 9 ] *)
; [9; 1; 1; 9] (* ; [ 9; 1; 1; 9; 6 ] *)
; [7; 2; 5] (* ; [ 7; 2; 5; 6; 6 ] *)
; [3] (* ; [ 3; 6; 6; 6; 6 ] *) ]
(* ] *)