• RedCAT (15/15) May 05 2017 Hello!
• bauss (35/50) May 05 2017 I would do something like this:
• bauss (3/7) May 05 2017 You could also do use alias this to use the delegate instead of
• RedCAT (2/4) May 06 2017 Thanks!

RedCAT <andronkin gmail.com> writes:

Hello!

Is it possible to create a list of slightly different delegates?

For example, there is a class hierarchy:

class Base;
class DerivedOne : Base;
class DerivedTwo : Base;

And there are several delegates:

void delegate(int, Base);
void delegate(int, DerivedOne);
void delegate(int, DerivedTwo);

It's easy to see that the only difference in the declarations of 
these delegates is the type of the second parameter, this is the 
class inherited from Base.

How can I create a list or an array where I can add these 
delegates?

bauss <jj_1337 live.dk> writes:

On Friday, 5 May 2017 at 14:20:43 UTC, RedCAT wrote:
 Hello!

 Is it possible to create a list of slightly different delegates?

 For example, there is a class hierarchy:

 class Base;
 class DerivedOne : Base;
 class DerivedTwo : Base;

 And there are several delegates:

 void delegate(int, Base);
 void delegate(int, DerivedOne);
 void delegate(int, DerivedTwo);

 It's easy to see that the only difference in the declarations 
 of these delegates is the type of the second parameter, this is 
 the class inherited from Base.

 How can I create a list or an array where I can add these 
 delegates?

I would do something like this:

interface IMyDelegate { }

final class MyDelegate(T) : IMyDelegate {
     private:
     void delegate(int, T) _d;

     public:
     this(void delegate(int, T) d) {
         _d = d;
     }

     void opCall(int x, T y) {
         _d(x, y);
     }
}

... Below is simple usage demonstration ...

private IMyDelegate[] _delegates;

void addDelegate(T)(void delegate(int, T) d) {
     _delegates ~= new MyDelegate!T(d);
}

auto getDelegate(size_t index) {
     return cast(MyDelegate!T)_delegates[index];
}

...

void func1(int, Base) { ... }
void func2(int, DerivedOne) { ... }
void func3(int, DerivedTwo) { ... }

...

addDelegate(&func1);
addDelegate(&func2);
addDelegate(&func3);

(getDelegate!Base)(100, base);
(getDelegate!DerivedOne)(100, derivedOne);
(getDelegate!DerivedTwo)(100, derivedTwo);

By theory that should work. It's untested, so you might need a 
few tweaks here and there.

bauss <jj_1337 live.dk> writes:

On Saturday, 6 May 2017 at 06:07:01 UTC, bauss wrote:
 On Friday, 5 May 2017 at 14:20:43 UTC, RedCAT wrote:
 [...]

 I would do something like this:

 [...]

You could also do use alias this to use the delegate instead of 
the class encapsulating the delegate.

RedCAT <andronkin gmail.com> writes:

On Saturday, 6 May 2017 at 06:07:01 UTC, bauss wrote:
 By theory that should work. It's untested, so you might need a 
 few tweaks here and there.

Thanks!