Re: [Boost-users] boost::range vs && (rvalue ref)

Subject: Re: [Boost-users] boost::range vs && (rvalue ref)
From: Neal Becker (ndbecker2_at_[hidden])
Date: 2013-01-11 07:19:33

Thorsten Ottosen wrote:

> On 11-01-2013 04:37, Nathan Ridge wrote:
>>
>>> Passing range by ref (&) is fine, but using (&&) results in and error. Any
>>> ideas?
>>>
>>> [snip]
>>
>>
>> When you pass by T&&, the deduced type of T will include the reference.
>> (So e.g. if you have a T&& argument and you pass in an int rvalue, T
>> will be deduced as 'const int&'. If you pass an int lvalue, T will
>> be deduced as 'int&'. This is in contrast to a regular reference, like
>> T&, where if you pass an int lvalue, T will be deduced as just 'int').
>>
>> Range metafunctions don't accept references to range types as their
>> input; you must pass the range type itself.
>>
>> So, you must call remove_reference<> on the deduced type 'T' prior to
>> passing it to a range metafunction.
>>
>>
>> I wonder if we should change the range metafunctions to accept
>> references to range types, and do the reference stripping
>> themselves?
> 
> I think we should. This has come up before.
> 
> -Thorsten

My objective is to support this common type of usage:

template<typename out_t>
F (out_t & o) {
}

F (boost::make_iterator_range (blah.begin(), blah.end()));