Re: [boost] [graph] ranges used by boost.graph not compatible with c++11 range-based-for

Subject: Re: [boost] [graph] ranges used by boost.graph not compatible with c++11 range-based-for
From: Jeremiah Willcock (jewillco_at_[hidden])
Date: 2013-10-03 11:26:57

On Thu, 3 Oct 2013, Nathan Ridge wrote:

>>> Sadly, I don't think there s a way of turn an std::pair of iterators into
>>> a range-based-for-compliant range (see [1]).
>>
>> correct me if I'm missing something, but when performing ADL the
>> namespaces of the template parameters
>> are in the set of associated namespaces. So, one could simply overload
>> begin/end in the namespace where
>> the iterator types are defined ...
>
> You're right, a per-namespace solution is possible. I don't think it can
> be done in general, though (i.e. for all std::pairs of iterators in one stroke).
>
> I'm not familiar with BGL - are the iterator types in question defined
> in a namespace under the library's control, or could they be user-provided
> types (in which the case the user would have to put the begin()/end()
> in their own namespace)?

For BGL-provided graph types, they are usually in a namespace under the 
library's control (I believe some are just std::vector<...>::iterator and 
similar, though).  For user-defined graph types, they can be from 
anywhere, and requiring begin and end would break backward compatibility.

-- Jeremiah Willcock