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.