Re: [boost] �

Subject: Re: [boost] �
From: Jeffrey Lee Hellrung, Jr. (jhellrung_at_[hidden])
Date: 2010-08-13 12:49:50

On 8/13/2010 9:16 AM, vicente.botet wrote:
> Hi,
> ----- Original Message -----
> From: "Jeffrey Lee Hellrung, Jr."<jhellrung_at_[hidden]>
> To:<boost_at_[hidden]>
> Sent: Friday, August 13, 2010 5:35 PM
> Subject: Re: [boost] [chrono] v0.4.5 Documentation update + warnings removal + bug fixes
>
>
>>
>> On 8/10/2010 11:00 AM, vicente.botet wrote:
>>> Hi,
>>>
>>> I have made some minor modifications to the Boost.Chrono library as requested on these mailing lists. The implementaton is stable.
>> ...
>>> Even if the review's date is not annonced yet, it will be great if some of you make a pre-review, so the conflicting issues are managed before the review.
>>
>> Is it necessary for common_type to fallback to Boost.TypeOf in the
>> absence of decltype?  In what situations is (bool ? T : U) not either T,
>> U, or some additional const/volatile qualifications on T or U, possibly
>> transposed with some reference or pointer qualifiers?
>>
>> In other words, when does (bool ? T : U) manufacture some new "3rd type"
>> out of the blue?
>
> (bool ? T : U) is incorrect as the ?: operator don't works on types but on expression. This is exactle the role of typeof. Are I'm missing something?

Okay, sorry, my fault for being lazy ;)  Replace (bool ? T : U) with (b 
? t : u); b of type bool; t of type T; u of type U; and t and u are 
rvalues unless T and U (respectively) are (lvalue) reference types.

Additionally, common_type operates on types, not expressions, so you 
know the types you're working with in the hypothetical conditional 
expression.

- Jeff