Hello all,
I'm coming to D from a background programming in C and C++, though I wouldn't
describe myself as an expert in either.
One of the C++ techniques I picked up over the last couple of years was the use
of policy classes, and I'm wondering how D addresses this issue of combining
various small components together to implement a given interface.
D's interfaces seem an obvious starting point, but from the documentation I've
read, it seems like each implementation has to be written separately. So, if I
have an interface,
interface FooBar {
void foo();
void bar();
}
... I can of course write two different implementations,
class FooBarOne : FooBar {
override void foo() {
// Foo function implementation
...
}
override void bar() {
// Bar function implementation
...
}
}
class FooBarTwo : FooBar {
override void foo() {
// Foo function implementation
...
}
override void bar() {
// Bar function implementation
...
}
}
... but suppose that I'd like the foo() function to be identical in both; how do
I avoid rewriting the code?
In C++ I'd think of a policy class,
template <class Foo, class Bar>
class FooBar : public Foo, public Bar {
...
};
and then have,
typedef FooBar<FooGeneric,BarOne> FooBarOne;
typedef FooBar<FooGeneric,BarTwo> FooBarTwo;
... but I don't see how to do something equivalent with D's interfaces and
implementations. Can anyone advise?
Thanks and best wishes,
-- Joe
