Anonymous class closures in g++

[Joel Dice]

Hi everyone.

I'm interested in extending g++ to support Java-style anonymous classes, 
and I thought I would ping this list in case anyone here has any relevant 
advice, experience, etc..

For those who don't know what I'm talking about, here's an example:

[snippet]

class Callback {
public:
  virtual ~Callback() { }
  virtual void handle(int result);
};

class A {
public:
  void process(int a, int b);
};

void foo(Callback* c);

int bar(A* a, int x) {
  // call foo with an instance of an anonymous subclass of Callback:
  foo(new Callback() {
    void handle(int result) {
      a->process(result, x);
    }
  });
}

[/snippet]

Now, if bar were implemented in valid C++, we'd have this much more 
verbose and brittle version:

[snippet]

int bar(A* a, int x) {
  class ClosureCallback: public Callback {
    Action* a;
    int x;
  public:
    ClosureCallback(Action* a, int x): a(a), x(x) { }
    void handle(int result) {
      a->process(result, x);
    }
  };

  foo(new ClosureCallback(a, x));
}

[/snippet]

Anyway, I'm just now starting to look at the g++ code to find out where 
code supporting this feature might fit.  If anyone else has any interest 
in this, please respond.  Thanks.

 - Joel