On 12/01/2016 03:51 PM, Payotz wrote:
> So, to give context, I am trying to make an event manager for a game I'm
> making.
> I was writing the "register()" method so I ran into a problem.
>
> The register method will take in delegates as an argument, but those
> delegates have varied arguments themselves, so I can't really put
> anything there.
What you know is how you will call them. Let's assume just an int argument.
> I know that it's got something to do with templates so I
> tried my hand in it and came up with this:
>
> void registerEvent(string event_name,T...)(T delegate() dg);
Binding state to callables is pretty easy in D. You don't want to pass
the arguments to the registration because it wouldn't know what to do
with those: Store the state for the delegate? Maybe, maybe not.
> I know there's something missing in the way I did it, so I'll be glad
> for you folks to tell me what I'm missing.
All you need is your interface to these callbacks.
> And for the second part of the question, I can't seem to make a Dynamic
> Array where I could store the delegates taken in the "registerEvent"
> method. Closest thing I have gotten to is this:
>
> private void delegate(T)(T args)[string] event;
>
> which resulted in the compiler screaming Error signs at me.
> So how does one do it?
Here is a start:
import std.stdio;
alias Func = void delegate(int);
Func[string] registry;
void register(string event_name, Func func) {
registry[event_name] = func;
}
struct S {
double d;
string s;
void foo(int i) {
writefln("S.foo called with %s; my state: %s", i, this);
}
}
void bar(int i) {
writefln("bar called with %s", i);
}
void main() {
register("trivial", (int a) => writefln("called with %s", a));
auto s = S(2.5, "hello");
register("with_struct", &s.foo);
int j;
register("using_local_state", (int a) {
++j;
writefln("Incremented local j: %s", j);
});
// This won't work as &bar because &bar is not a delegate, but a
function.
// Very simple with toDelegate.
// http://dlang.org/phobos/std_functional.html#toDelegate
import std.functional: toDelegate;
register("regular_function", toDelegate(&bar));
foreach (event_name, func; registry) {
writefln("--- Calling function registered for %s", event_name);
func(cast(int)event_name.length);
}
}
Ali
