[boost] Re: is_base_and_derived question

From: Gennaro Prota (gennaro_prota_at_[hidden])
Date: 2003-01-31 13:30:09

On Fri, 31 Jan 2003 12:14:09 -0500, David Abrahams
<dave_at_[hidden]> wrote:

>I'd rather settle on one for the sake of simplicity and see if it's
>enough for people.  Once you provide two interfaces, you're sort of
>stuck supporting them both.

Well, then I imagine you would prefer the old semantics. Was there
anybody complaining that being not enough?

Maybe however it would be nice to see if we find an use for the new
semantics. I don't know what it could be but probably knowing that
private or ambiguous base classes are detectable without errors will
encourage someone to find an use for that. This wouldn't certainly be
a new experience for C++, since it has happened with templates or e.g.
with function call expressions as operand of sizeof. Similarly knowing
widely unknown rules about conversion ranking allowed Rani to find
their application.

In fact, the 'old' version is implementable in terms of the new one,
but not with compilers that can't digest the latter, of course. The
maintenance/supporting burden you refer to seems mainly due to broken
compilers :-/

Genny.