Re: [boost] [fusion] transform into vector

From: shunsuke (pstade.mb_at_[hidden])
Date: 2007-11-22 19:31:16

Joel de Guzman wrote:
>> transform_view, in order to implement `deref` etc, uses `result_of`
>> in the standard manner, where `result<F(int)> means that rvalue is passed.
> 
> Correction: result<F(int&)> which means lvalue is passed.
> The lvalue is correctly propagated through the transform.

No. By the standard, `result<F(int)>` means that rvalue is passed,
and `result<F(T&)>` means that lvalue is passed.

>> But, as_vector applied to transform_view uses `result_of` in a strange manner
>> through value_of.
>>
>> A FunctionObject for transform_view requires two result_of implementations;
>> It seems impossible.
> 
> I provided an example, didn't I?

That doesn't work with rvalues.
With regard to standard manner, result<> implementation of `f` is wrong.
So, that does't work with transform_view.

> Actually, there's another way to do
> it -- take a look at how fusion zip does it.

I will apply that way(Preprocessor programming)
if no workaround is found.

Regards,

-- 
Shunsuke Sogame