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Subject: Re: [boost] [fusion] patch for #5010
From: Jürgen Hunold (juergen.hunold_at_[hidden])
Date: 2011-12-21 09:10:18


Hi Joel,

On Wednesday, 21. December 2011 06:24:01 Joel de Guzman wrote:
> On 12/21/2011 8:49 AM, Mathias Gaunard wrote:
> > On 12/21/2011 01:03 AM, Joel de Guzman wrote:
> >> I was hesitant to have this fix because "nil" is actually part of the
> >> API. But, given how pervasive this problem is, it seems the best way
> >> to go is to accept the fix and break backward compatibility :(
> >> We might have to issue a warning in the docs.
> >>
> >> I'll apply the patches (change nil to nil_). Thomas, I'm CC'ing you
> >> for the heads up.
> >
> > You could add a typedef of nil_ to nil if you detect that you're not in
> > Objective-C++ mode (i.e. check for __OBJC__ or similar)
>
> That was my recommendation in the other (related) ticket. But it seems
> it's not a problem unique to Objective-C++. LEDA was also mentioned.
> Anything else? If it's just Objective-C++ and LEDA, then I might just
> have to ask for a patch with the appropriate #ifdefs for these problematic
> compilers/libraries.
>
> Let's hear from the OP.

Well, I'm not the OP (at least for the trac tickets ;-)) but I've created a
simple patch providing the typedef in boost/fusion/container/list/cons_fwd.hpp
if neither LEDA nor Objective-C are used.

I doubt if the place is correct, but the logic works works.

And while were at it: I have noticed that a lot of headers simply forward
"nil" with "struct nil;" instead of using "cons_fwd.hpp"

And the typedef should somehow be marked as "deprecated" when used, if this is
possible.

Yours,

Jürgen

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