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From: Simon Buchan (simon_at_[hidden])
Date: 2005-09-26 17:53:48

Graeme Prentice wrote:
>>-----Original Message-----
>>From: boost-bounces_at_[hidden]
>>[mailto:boost-bounces_at_[hidden]] On Behalf Of Simon Buchan
>>Graeme Prentice wrote:
>><snipped big header>
> Six lines is big?
Yep. For a header. Consider how big the headers for a quote nested 3
or 4 levels deep would get.

>>You mean:
>> template <class T>
>> void foo( typename bar<T>::baz froble) {...}
>>is fine, but:
>> template <class T>
>> void foo( typename bling::bar<T>::baz froble) {...}
>>isn't? That sounds like a language flaw!
> No, neither is fine. bar<T> is a non-deduced context in both cases. What
> makes you think the first case is fine?
> There's a good reason for this restriction even though it's a surprise when
> you first meet it.
Huh. Was I thinking of bar<T> and bar<T>::baz, then? (I have no idea
what I was thinking, I wrote that at something like 4AM :D)
>>>>(Background info: I would like to use this technique to generate
>>>>optimized forwarding functions that do not know anything about the
>>>>function being forwarded to. Overloads taking any number of params
>>>>would be generated with the boost preprocessor library.)
>>>It might be better to write specializations for foo rather
>>than specify the
>>>types at the point of call.
>>Doesn't that defeat the point of a forwarding function? I agree that
>>it's better than most of the alternatives, though.
> How does it defeat the point of a forwarding function?
> Do you mean it contradicts the requirement of the forwarding function not
> knowing anything about the function being forwarded to? If the
> specializations (or overloads) provided are the same as the call_traits
> ones, then the forwarding function still doesn't know anything about the
> function being forwarded to. Chances are the forwarding function will be
> inlined and the parameter types of the forwarding function won't matter so a
> single forwarding function that passes by value might do. Using call_traits
> might even be less efficient.
*shrug*, I guess. I probably don't quite understand what he's trying to do.

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