Re: minimal object.d implementation that allows classes

[Jean-Louis Leroy via Digitalmars-d]

On Thursday, 7 December 2017 at 15:09:45 UTC, Jean-Louis Leroy 
wrote:
On Thursday, 7 December 2017 at 14:59:57 UTC, Steven 
Schveighoffer wrote:
The object is constructed here: [...]

Thanks for the pointers, you've saved me a lot of time :)

On a side note however, you really shouldn't change data in a 
ClassInfo at all, and probably the compiler shouldn't let you!

This experiment is related to an ongoing discussion with 
Walter, Andrei and Ali on extending D with general mechanisms 
to better support libraries like openmethods. I will post in 
Studies soon.

Cool:

import std.stdio;

class Foo {
  abstract void report();
}

class Bar : Foo {
  override void report() { writeln("I'm fine!"); }
}

void main() {
  auto oldPtr = Bar.classinfo.vtbl.ptr;
  Bar.classinfo.vtbl.reserve(1000);
  Bar.classinfo.vtbl.ptr[Bar.classinfo.vtbl.length] = cast(void*) 
0x123456;
  writeln(oldPtr != Bar.classinfo.vtbl.ptr); // true
  *cast(void***) Bar.classinfo.m_init.ptr = 
Bar.classinfo.vtbl.ptr;
  Foo foo = new Bar();
  writeln(oldPtr == *cast(void***)foo); // false
  foo.report(); // I'm fine!
  writeln((*cast(void***)foo)[Bar.classinfo.vtbl.length]); // 
123456
}