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Alias std.typecons.BlackHole
BlackHole!Base
is a subclass of Base
which automatically implements
all abstract member functions in Base
as do-nothing functions. Each
auto-implemented function just returns the default value of the return type
without doing anything.
The name came from Class::BlackHole Perl module by Sean M. Burke.
Parameters
Name | Description |
---|---|
Base | A non-final class for BlackHole to inherit from. |
See Also
Example
import std .math : isNaN;
static abstract class C
{
int m_value;
this(int v) { m_value = v; }
int value() @property { return m_value; }
abstract real realValue() @property;
abstract void doSomething();
}
auto c = new BlackHole!C(42);
writeln(c .value); // 42
// Returns real.init which is NaN
assert(c .realValue .isNaN);
// Abstract functions are implemented as do-nothing
c .doSomething();
Authors
Andrei Alexandrescu, Bartosz Milewski, Don Clugston, Shin Fujishiro, Kenji Hara
License
Copyright © 1999-2022 by the D Language Foundation | Page generated by ddox.