Stdlib.Option(3)                 OCaml library                Stdlib.Option(3)

NAME
       Stdlib.Option - no description

Module
       Module   Stdlib.Option

Documentation
       Module Option
        : (module Stdlib__Option)









   Options
       type 'a t = 'a option =
        | None
        | Some of 'a


       The type for option values. Either None or a value Some v .



       val none : 'a option


       none is None .



       val some : 'a -> 'a option


       some v is Some v .



       val value : 'a option -> default:'a -> 'a


       value o ~default is v if o is Some v and default otherwise.



       val get : 'a option -> 'a


       get o is v if o is Some v and raise otherwise.


       Raises Invalid_argument if o is None .



       val bind : 'a option -> ('a -> 'b option) -> 'b option


       bind o f is f v if o is Some v and None if o is None .



       val join : 'a option option -> 'a option


       join oo is Some v if oo is Some (Some v) and None otherwise.



       val map : ('a -> 'b) -> 'a option -> 'b option


       map f o is None if o is None and Some (f v) if o is Some v .



       val product : 'a option -> 'b option -> ('a * 'b) option


       product o0 o1 is Some (v0, v1) if o0 is Some v0 and o1 is Some
           v1 and None otherwise.


       Since 5.5



       val fold : none:'a -> some:('b -> 'a) -> 'b option -> 'a


       fold ~none ~some o is none if o is None and some v if o is Some v .



       val iter : ('a -> unit) -> 'a option -> unit


       iter f o is f v if o is Some v and () otherwise.



       val blend : ('a -> 'a -> 'a) -> 'a option -> 'a option -> 'a option


       blend f o1 o2 is o1 if o2 is None , o2 if o1 is None , and Some (f v1
       v2) if o1 is Some v1 and o2 is Some v2 .


       Since 5.5



       val for_all : ('a -> bool) -> 'a option -> bool


       for_all p behaves like List.for_all p on a list of zero or one element:

       - for_all p None is true ,

       - for_all p (Some v) is p v .



       Since 5.5



       val exists : ('a -> bool) -> 'a option -> bool


       exists p behaves like List.exists p on a list of zero or one element:

       - exists p None is false ,

       - exists p (Some v) is p v .



       Since 5.5




   Predicates and comparisons
       val is_none : 'a option -> bool


       is_none o is true if and only if o is None .



       val is_some : 'a option -> bool


       is_some o is true if and only if o is Some o .



       val equal : ('a -> 'a -> bool) -> 'a option -> 'a option -> bool


       equal eq o0 o1 is true if and only if o0 and o1 are both None or if
       they are Some v0 and Some v1 and eq v0 v1 is true .



       val compare : ('a -> 'a -> int) -> 'a option -> 'a option -> int


       compare cmp o0 o1 is a total order on options using cmp to compare
       values wrapped by Some _ .  None is smaller than Some _ values.




   Converting
       val to_result : none:'e -> 'a option -> ('a, 'e) result


       to_result ~none o is Ok v if o is Some v and Error none otherwise.



       val to_list : 'a option -> 'a list


       to_list o is [] if o is None and [v] if o is Some v .



       val to_seq : 'a option -> 'a Seq.t


       to_seq o is o as a sequence.  None is the empty sequence and Some v is
       the singleton sequence containing v .




   Syntax
       module Syntax : sig end


       Binding operators. See manual section 12.23 for details.


       Since 5.5



OCamldoc                          2026-06-22                  Stdlib.Option(3)