Option

# Module Option

    module Option: sig .. end

Functions for the option type.

Options are an Ocaml standard type that can be either `None` (undefined) or `Some x` where x can be any value. Options are widely used in Ocaml to represent undefined values (a little like NULL in C, but in a type and memory safe way). This module adds some functions for working with options.

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

`may f (Some x)` calls `f x` and `may f None` does nothing.

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

`map f (Some x)` returns `Some (f x)` and `map None` returns `None`.

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

`default x (Some v)` returns `v` and `default x None` returns `x`.

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

`map_default f x (Some v)` returns `f v` and `map_default f x None` returns `x`.

    val is_none : 'a option -> bool

`is_none None` returns `true` otherwise it returns `false`.

    val is_some : 'a option -> bool

`is_some (Some x)` returns `true` otherwise it returns `false`.

    val get : 'a option -> 'a

`get (Some x)` returns `x` and `get None` raises `No_value`.

    exception No_value

Raised when calling `get None`.