A new boost::any feature?

From: Itay Maman (itay_maman_at_[hidden])
Date: 2001-11-27 07:01:32

I know I am taking a risk in bringing this up, since it is possible 
that this very suggestion has been discussed and decided. (I did an 
extensive search - which yielded nothing -  but still...)

The feature I was thinking of, can be titled as 'applying an 
operation on any's value' (in a type-safe way). E.g: I'd like to send 
the value held by a boost::any object to cout, but I don't want to 
use any_cast<>, since this forces me to add a specific any_cast<> 
call for each type.

The client code should look something along these lines:

     struct my_functor {
        ....
     }

     boost::any a1('A');
     a1.apply_the_operation(my_functor());

     a1 = 222;
     a1.apply_the_operation(my_functor());

If my_functor is defined to send its operand to cout, then  I would 
expect the above code to yield the following output:
  A
  222

Has this been discussed yet?

(I have written an any implementation which supports that, but having 
read Henney's views on adding template parameters to any, I am not 
sure he's going to like it).