Re: [boost] Iterator Range and operator==

Subject: Re: [boost] Iterator Range and operator==
From: Dave Abrahams (dave_at_[hidden])
Date: 2012-04-21 05:33:30

on Sat Apr 21 2012, Olaf van der Spek <ml-AT-vdspek.org> wrote:

> On Fri, Apr 20, 2012 at 3:19 PM, Mathias Gaunard
> <mathias.gaunard_at_[hidden]> wrote:
>> On 20/04/12 14:15, Olaf van der Spek wrote:
>>>
>>> Hi,
>>>
>>> What do you expect this code to do? Is b true or false? And why?
>
>>> Is this expected behaviour?
>>>
>>> #include<boost/range/iterator_range.hpp>
>>> #include<string>
>>>
>>> int main()
>>> {
>>> Â  Â  Â  Â  std::string s = "Olaf";
>>> Â  Â  Â  Â  boost::iterator_range<std::string::iterator> Â r(s);
>>> Â  Â  Â  Â  bool a = r == s;
>>
>>
>> a is true.
>>
>>
>>> Â  Â  Â  Â  bool b = r == "Olaf";
>>
>>
>> b is false, "Olaf" is one character longer than r.
>
> It is current behaviour. But is it expected behaviour?

Yes.  Until the language gives us a way to distinguish string literals
from other arbitrary arrays of char, it's the best we can do.  The
alternative is to have generic code suddenly stop working when T==char.

Regards,

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com