Re: [boost] any

From: Kevlin Henney (kevlin_at_[hidden])
Date: 2000-09-04 07:47:41

In message <01a701c0166a$bb06bfa0$3e0524d4_at_pdimov>, Peter Dimov
<pdimov_at_[hidden]> writes
>How about listing what you think are its
>> defining features, and from that drawing a name that seems to capture
>> this or at least part of it?
>
>To paraphrase Scott Meyers, ref<T> is an object that is designed to act,
>look and feel like the value it holds.

This does not seem to be a summary of its defining features: This is an
unfulfillable wish list!

>> A little, but the idea of a customised double and single dispatch engine
>> was what I had in mind;
>
>In this case, having a boost-accepted double dispatch engine would be a
>start.

One step at a time ;-)

>I think that you should explain this extended_any concept in more detail.
>How does the user layer an operator+ on top of any? How are the possible
>conversions controlled by the user? How is any(int) + any(std::string)
>handled, i.e. is this an int or a string?

That, I would contend, is a separate topic. As I said, this is something
to look at, but is not the aim of the current any proposal. I would
envisage that an extended_any would be a templated type that would adapt
an any and provide features according to its template parameter.
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