Re: [boost] [range] [general] making member functions SFINAE-friendly

Subject: Re: [boost] [range] [general] making member functions SFINAE-friendly
From: Jeff Flinn (Jeffrey.Flinn_at_[hidden])
Date: 2013-02-21 11:06:00

On 2/21/2013 5:18 AM, Thorsten Ottosen wrote:
> On 20-02-2013 22:12, Neil Groves wrote:
>> On Wed, Feb 20, 2013 at 9:02 PM, Jeffrey Lee Hellrung, Jr. <
>> jeffrey.hellrung_at_[hidden]> wrote:
>>
>>> On Wed, Feb 20, 2013 at 12:55 PM, Neil Groves <neil_at_[hidden]
>>>> wrote:
>>> [...]
>>>
>>>> I agree. My suggestion didn't have a new base class. I think by making
>>>> boost::size(rng) call range_size(rng) we can provide an extension
>>>> method
>>>> similar to that already provided for boost::begin(rng) and
>>> boost::end(rng).
>>>>
>>>
>>> You mean like range_calculate_size [1] ?
>>>
>>> Exactly I thought that when I introduced this it has been quite
>> successful, and that we could build upon this by adding the optimal
>> implementations for standard library components. I have been using
>> this as
>> an extension mechanism privately in this manner for a while and it has
>> worked well for me. I wanted to get other peoples views on this solution
>> before making the extension mechanism more widely used and optimised by
>> default for the standard library containers.
>
> I would like to keep boost::size() O(1). Anybody that writes code
> relying on boost::size() should know that this is guaranteed.
>
> As I understand it, there is a wish from some users to get a size even
> when O(1) time is not possible. This suggest to me that we also need to
> extend boost::distance() to work for containers.

+1

Jeff