Re: A comparison between C++ and D

[John Colvin via Digitalmars-d]

On Wednesday, 9 March 2016 at 20:14:13 UTC, Adam D. Ruppe wrote:
---
import std.stdio;
@nogc int delegate(int) dg;

int helper() @nogc {
        int a = 50;

        struct MyFunctor {
                int a;

                @nogc this(int a) { this.a = a; }

                // the function itself
                @nogc int opCall(int b) { return a+b; }
        }

        // capture a by value
        // WARNING: I stack allocated here but
        // set it to a global var, this is wrong;
        // it should probably be malloc'd, but since
        // I know I am just using it here, it is OK
        auto myfunc = MyFunctor(a);

        dg = &myfunc.opCall;

        return dg(10);
}

void main() {
        writeln(helper());
}

typeof(&myfunc.opCall) == int delegate(int b) @nogc

what magic is this? I had no idea that taking the address of 
opCall would give me a delegate.