From: Dill, John (john-dill_at_[hidden])
Date: 2004-05-07 09:54:35
"Douglas Gregor" <gregod_at_[hidden]> wrote in message news:<200405071039.24725.gregod_at_[hidden]>...
> On Friday 07 May 2004 10:30 am, Dill, John wrote:
> > I see your point. But, what if instead of argument_traits being pass by
> > value, it by default passes by T const&? What could be done is to have the
> > bind_t arguments be passed by const reference, and then use
> > reference_wrapper to do type-selection to pass by reference. It still
> > supports literals, and passes by T const& when it can, but everything that
> > is passed by reference must have a ref( object ). The compiler would fail
> > if you try to pass a reference without a reference_wrapper because it by
> > default tries to pass a T const&. This wouldn't require the 2^N overloads
> > but would require you to do a ref( object ) for everything passed by
> > reference. This might also be a workaround for those compilers that don't
> > support T& and T const& overloading.
> So we'd be trading lvalue support for literal support. In my experience,
> lvalues are _much_ more important than literals[*], and we've had these
> semantics for a really long time (they'll be part of the C++ Library TR), so
> it will take a truly killer argument to change this.
> [*] Thinking of my own work, where I use lots of bind expressions, I remember
> only once having to name a temporary to get around the T& issue with bind,
> but can thinking of at least 4 places where I pass lvalues through bind.
Okay, just trying an idea out. Thanks for your comments.
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