Optional

A simple wrapper around a value to make it optionally present.

struct Optional (

T

) {

static Optional!T of(T value);

static Optional!T of(Nullable!T nullableValue);

static Optional!T empty();

Nullable!T asNullable();

T orElse(T defaultValue);

T orElseThrow(string msg);

T orElseThrow(Exception delegate() exceptionSupplier);

bool opCast();

}

Members

Functions

asNullable Nullable!T asNullable(): Converts this optional to a Phobos-style Nullable.
opCast bool opCast(): Provides a mechanism to allow usage in boolean expressions.
orElse T orElse(T defaultValue): Gets the value of this optional if it exists, otherwise uses a given default value.
orElseThrow T orElseThrow(string msg): Gets the value of this optional if it exists, or throws an exception.
orElseThrow T orElseThrow(Exception delegate() exceptionSupplier): Gets the value of this optional if it exists, or throws an exception as produced by the given delegate.

Static functions

empty Optional!T empty(): Constructs an optional that's empty.
of Optional!T of(T value): Constructs an optional value using a given value.
of Optional!T of(Nullable!T nullableValue): Constructs an optional value using a Phobos nullable.

Variables

isNull bool isNull;: Whether this optional is empty.
value T value;: The internal value of this optional.

handy_httpd components optional functions

mapIfPresent

structs

Optional