Re: [boost] Re: Review: Base from Member

From: Ed Brey (edbrey_at_[hidden])
Date: 2001-08-01 08:04:16

From: "Daryle Walker" <darylew_at_[hidden]>

> on 7/30/01 1:34 PM, Ed Brey at edbrey_at_[hidden] wrote:
>
> OK.  (The "ron_" name was the last way of honoring the discoverer of
the
> technique.)

I gathered as much.  That can be fine for concept names like Koenig
lookup (and only major concepts at that), but rarely appropriate for a
programatic name.

> -   Cannot work if the compiler doesn't support member templates

For a helper class that can easily be done without, there is little
penalty in leaving behind a few nonconforming compilers.  A larger
penalty would be compromising the interface to appease the few.

> -   C++ syntax gives no way of specifying the template parameters of a
>     constructor member template (unlike any other kind of template).
It
>     depends on argument deduction only.  Could this be a potential
problem?

It is equivalent to calling the constructor of the member directly
through the base class that the user would otherwise have to write by
hand.

> I wonder if the pre-processor library can help in automating this?

I'm not sure.  It's definately worth looking into.

> > More specifically, the example should show the member variable being
> > passed by reference to the other constructor, since this is often
best
> > practice and avoids the complexity of needing the this-> prefix for
a
> > pointer.  This complexity is better presented in a subsequent
example,
> > so that too much new material is not presented at once.
>
> Actually, the rationale example needs the "this->" to work.

Right, since the existing rationale example uses a pointer.  My point
was that an example that uses a reference won't need "this->", and so
would make for a simpler example.  (A more complicated example that used
a pointer and "this->" could then follow.)