Re: [boost] Boost.Preprocessor: Alternatives to defined(x)

From: Paul Mensonides (pmenso57_at_[hidden])
Date: 2003-01-05 19:17:03

----- Original Message -----
From: "Vesa Karvonen" <vesa_karvonen_at_[hidden]>
To: <boost_at_[hidden]>
Sent: Sunday, January 05, 2003 3:45 PM
Subject: Re: [boost] Boost.Preprocessor: Alternatives to defined(x)

> David Abrahams:
> > > Paul Mensonides:
> > > > The semantic change is that 'x' must not be a function-like macro.
>                                            ^^^
> [...]
> >How can you use a macro which only tells you if a function-like macro
> >is defined to tell you if an object-like macro is defined?
>
> >If we could do that, couldn't you implement your original intended
> >semantics?
>
> Well, yes. It could be used for testing whether an object-like config
macro
> has been defined.
>
> Actually, since it is not currently possible (portable) to pass around
empty
> parameters, it really shouldn't make much difference that function-like
> macros may not be tested.

That is why I said the semantic change was minor.  The major difference is
that it disallows passing any function-like macro that takes any arguments
into the IS_EMPTY macro.  It can still be used to test object-like macros.
Anyway, I might still be able to make the original ideal work with VC and
Metrowerks.  (You wouldn't believe how sick I am of those two compilers!)
Give me some time....

Paul Mensonides