On Sunday, 9 August 2020 at 12:24:05 UTC, Steven Schveighoffer
wrote:
On 8/9/20 5:16 AM, lexxn wrote:
I'm trying to get the factory pattern going with classes
class A {}
class B {}
class C {}
auto getClassById(uint id)
{
if (id == 0) {
return cast(A)Object.factory("A");
} else if(id == 1) {
return cast(B)Object.factory("B");
} else {
return cast(C)Object.factory("C");
}
}
I'm getting 2 errors:
main.d(69): Error: Expected return type of main.A, not main.B:
main.d(67): Return type of main.Ainferred here.
Change your return type to Object.
Also is it possible to completely skip the getClassById
function and if I've and array string classes = ["A", "B"] to
just cast(classes[0])Object.factory(classes[0]);. I understand
that I need to cast classes[0].
This won't work.
If you know what your class is going to be, I'd just import the
file that contains it and avoid the whole Object.factory deal.
It's going to go away anyways.
In other words:
Object getClassById(uint id)
{
if (id == 0) {
return new A;
} else if(id == 1) {
return new B;
} else {
return new C;
}
}
-Steve
I assume that the correct syntax for the getClassById is
Object getClassById(uint id) {
if (id == 0) {
return new A();
} else if (id == 1) {
return new B();
} else {
return new C();
}
}
or maybe I'm wrong. This way if I try auto myClass =
getClassById(0) and if I've a method in A,B&C classes when I try
to call it with myClass I get no property methodName for type
object.Object.
