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) {
            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);


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