Manually allocate delegate?

[Jack Applegame via Digitalmars-d-learn]

On Sunday, 12 July 2015 at 08:38:01 UTC, Tofu Ninja wrote:
> Is it even possible?

You can use function instead delegate, and bind captured 
variables as struct:

http://dpaste.dzfl.pl/6e23bbcfe17f

auto bind(F: R function(ARGS), R, ARGS...)(F fn, ARGS args) @nogc 
{
	struct Functor {
		F fn;
		ARGS args;
		this(F fn_, ARGS args_) {
			fn = fn_;
			args = args_;
		}
		R opCall() { return fn(args); }
	}
	return Functor(fn, args);
}

import std.stdio;

auto foo(int x) {
    static int bar(ref int x){ return x++; }
    return bind(&bar, x);
}

void main() {
	auto f1 = foo(5);
	auto f2 = foo(10);
	writefln("%s, %s, %s", f1(), f1(), f1());
	writefln("%s, %s, %s", f2(), f2(), f2());
}