Module Accessor_base__.Accessor_option

include sig ... end with type 'a t := 'a Base.Option.t
type 'a t =
| None
| Some of 'a
include module type of sig ... end
val none : ('a -> unit -> unit, 'a -> 'b t -> 'b t[< Accessor_base__.Import.Accessor.variant ]) Accessor_base__.Import.Accessor.t
val some : ('a -> 'b -> 'c'a -> 'b t -> 'c t[< Accessor_base__.Import.Accessor.variant ]) Accessor_base__.Import.Accessor.t
val default : 'a -> is_default:('b -> Base.bool) -> ('i -> 'a -> 'b'i -> 'a Base.option -> 'b Base.option[< Accessor_base__.Import.isomorphism ]) Accessor_base__.Import.Accessor.t

default x ~is_default is an isomorphism between an option and its contents, where None is considered the same as default. is_default x is expected to be true.

  • get (default _ ~is_default:_) (Some y) = y
  • get (default x ~is_default:_) None = x
  • construct (default _ ~is_default) y = if is_default y then None else Some y

Note that, as explained in the Accessor documentation, well-behaved isomorphisms are expected to satisfy the following properties:

  • get (construct b) = b
  • construct (get at) = at

However, if is_default b = true, both properties can be violated:

  • get (construct b) = get None = x (violation if x <> b)
  • construct (get (Some b)) = construct b = None
include Accessor_base__.Import.Accessor.Monad.S with type 'a t := 'a Base.option
type 'a t
include Accessor__.Applicative_signatures_intf.Monad_s2 with type ('a, _) t := 'a t
type ('inner, 'outer, 'kind) accessor
type 'a optional_args
type ('a, 'e) t
val map : ((Base.unit -> 'a -> 'bBase.unit -> 'at -> 'bt[> Accessor.Subtyping.many ]) accessor -> 'at -> f:('a -> ('b'e) t) -> ('bt'e) t) optional_args
val mapi : (('i -> 'a -> 'bBase.unit -> 'at -> 'bt[> Accessor.Subtyping.many ]) accessor -> 'at -> f:('i Accessor.Index.t -> 'a -> ('b'e) t) -> ('bt'e) t) optional_args
val all : (Base.unit -> ('a'e) t -> 'aBase.unit -> 'at -> 'bt[> Accessor.Subtyping.many ]) accessor -> 'at -> ('bt'e) t
val all_unit : (Base.unit -> (Base.unit'e) t -> _Base.unit -> 'at -> _[> Accessor.Subtyping.many_getter ]) accessor -> 'at -> (Base.unit'e) t
val iter : ((Base.unit -> 'a -> _Base.unit -> 'at -> _[> Accessor.Subtyping.many_getter ]) accessor -> 'at -> f:('a -> (Base.unit'e) t) -> (Base.unit'e) t) optional_args
val iteri : (('i -> 'a -> _Base.unit -> 'at -> _[> Accessor.Subtyping.many_getter ]) accessor -> 'at -> f:('i Accessor.Index.t -> 'a -> (Base.unit'e) t) -> (Base.unit'e) t) optional_args
val sum : ((module Base.Container.Summable with type t = 'sum) -> (Base.unit -> 'a -> _Base.unit -> 'at -> _[> Accessor.Subtyping.many_getter ]) accessor -> 'at -> f:('a -> ('sum'e) t) -> ('sum'e) t) optional_args
val sumi : ((module Base.Container.Summable with type t = 'sum) -> ('i -> 'a -> _Base.unit -> 'at -> _[> Accessor.Subtyping.many_getter ]) accessor -> 'at -> f:('i Accessor.Index.t -> 'a -> ('sum'e) t) -> ('sum'e) t) optional_args
val count : ((Base.unit -> 'a -> _Base.unit -> 'at -> _[> Accessor.Subtyping.many_getter ]) accessor -> 'at -> f:('a -> (Base.bool'e) t) -> (Base.int'e) t) optional_args
val counti : (('i -> 'a -> _Base.unit -> 'at -> _[> Accessor.Subtyping.many_getter ]) accessor -> 'at -> f:('i Accessor.Index.t -> 'a -> (Base.bool'e) t) -> (Base.int'e) t) optional_args
val map_reduce : ((Base.unit -> 'a -> _Base.unit -> 'at -> _[> Accessor.Subtyping.many_getter ]) accessor -> 'at -> empty:'b -> combine:('b -> 'b -> 'b) -> f:('a -> ('b'e) t) -> ('b'e) t) optional_args
val map_reducei : (('i -> 'a -> _Base.unit -> 'at -> _[> Accessor.Subtyping.many_getter ]) accessor -> 'at -> empty:'b -> combine:('b -> 'b -> 'b) -> f:('i Accessor.Index.t -> 'a -> ('b'e) t) -> ('b'e) t) optional_args
val map_reduce_nonempty : ((Base.unit -> 'a -> _Base.unit -> 'at -> _[> Accessor.Subtyping.nonempty_getter ]) accessor -> 'at -> combine:('b -> 'b -> 'b) -> f:('a -> ('b'e) t) -> ('b'e) t) optional_args
val map_reduce_nonemptyi : (('i -> 'a -> _Base.unit -> 'at -> _[> Accessor.Subtyping.nonempty_getter ]) accessor -> 'at -> combine:('b -> 'b -> 'b) -> f:('i Accessor.Index.t -> 'a -> ('b'e) t) -> ('b'e) t) optional_args