On Sat, 22 Jun 2013 18:58:22 +0200, deed <n...@none.none> wrote:
class A { ... }
class NonContainer : A { ... }
class Container : A { A[] container; }
class NC1 : NonContainer {}
...
class C1 : Container {}
...
A getO(string info)
{
switch (info)
{
default : return new NonContainer();
case "info1": return new C1();
case "info2": return new NC1();
case "info3": return new Container();
case "info4": return new NonContainer();
...
}
}
void foo()
{
auto o = getO("some information");
if (is(typeof(o) == Container) { ... } // Doesn't work.
// Type is always A.
...
}
Is there a way to make getO return the most specialized type of the
instantiated object in the switch statement to enable this pattern?
The type of an expression in D is determined at compile time, and getO
returns an A. Hence, o will always have static type A, and is(typeof(...
only checks the static type.
If you want to check the dynamic (run-time) type of o, you should
instead see if it is castable to Container:
auto o = getO("info3");
if (cast(Container)o != null) { ... }
--
Simen
