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std.typecons.Nullable.get - multiple declarations

Function Nullable.get

Gets the value if not null. If this is in the null state, and the optional parameter fallback was provided, it will be returned. Without fallback, calling get with a null state is invalid. This function is also called for the implicit conversion to T.

inout ref inout(T) get() pure nothrow @property @safe;

inout auto get(U) (
  inout(U) fallback
) pure nothrow @property @safe;

Parameters

NameDescription
fallback the value to return in case the Nullable is null.

Returns

The value held internally by this Nullable.

Example

import core.exception : AssertError;
import std.exception : assertThrown, assertNotThrown;

Nullable!int ni;
int i = 42;
//`get` is implicitly called. Will throw
//an AssertError in non-release mode
assertThrown!AssertError(i = ni);
writeln(i); // 42

ni = 5;
assertNotThrown!AssertError(i = ni);
writeln(i); // 5

Example

int i = 42;
Nullable!int ni2;
int x = ni2.get(i);
writeln(x); // i

ni2 = 7;
x = ni2.get(i);
writeln(x); // 7

Function Nullable.get

Gets the value. this must not be in the null state. This function is also called for the implicit conversion to T.

inout ref inout(T) get() @property;

Preconditions

isNull must be false.

Returns

The value held internally by this Nullable.

Example

import std.exception : assertThrown, assertNotThrown;

Nullable!(int, -1) ni;
//`get` is implicitly called. Will throw
//an error in non-release mode
assertThrown!Throwable(ni == 0);

ni = 0;
assertNotThrown!Throwable(ni == 0);

Authors

Andrei Alexandrescu, Bartosz Milewski, Don Clugston, Shin Fujishiro, Kenji Hara

License

Boost License 1.0.