Skip to main content
Version: Next

Option Module

Option.defaultValue : 'a -> 'a option -> 'a​

Returns option value or a fallback.

let port = Some 8080 |> Option.defaultValue 80

Option.defaultWith : (unit -> 'a) -> 'a option -> 'a​

Computes fallback lazily.

let value = None |> Option.defaultWith (fun () -> 42)

Option.isNone : 'a option -> bool​

Returns true when option is None.

let missing = None |> Option.isNone

Option.isSome : 'a option -> bool​

Returns true when option is Some.

let present = Some "x" |> Option.isSome

Option.map : ('a -> 'b) -> 'a option -> 'b option​

Transforms value inside Some.

let upper = Some "fscript" |> Option.map String.toUpper