question about foreach, opApply, and delegates

[Jerry Quinn]

Hi, all.  I find myself a little confused about how foreach, opApply, and delegates interact according to the docs.

Foreach on an aggregate will use the opApply call (assuming ranges aren't being used).  So if we use a simple example below, what exactly is the delegate that is passed to opApply?  The docs say a delegate is a pairing of an object reference and a function, where the object is passed as the 'this' parameter to the function.  But that doesn't seem to be the case here.

Is a virtual object with a function encompassing the body of the foreach being silently created and passed in?

Thanks,
Jerry


class C {
  uint[] a;
  int opApply(int delegate(ref uint) dg) {
    int result = 0;
    for (size_t i=0; i < a.length; i++) {
      result = dg(a[i]);
      if (result) break;
    }
    return result;
  }
}
void foo() {
  C c = new C;
  foreach (uint v; c) { writefln(v); }
}