Re: [boost] [utility] string_ref construction from rvalue reference to string

Subject: Re: [boost] [utility] string_ref construction from rvalue reference to string
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2014-08-03 08:55:59

On Sunday 03 August 2014 16:27:13 Andrey Davydov wrote:
> On Sat, Aug 2, 2014 at 2:46 AM, Nathan Crookston <nathan.crookston_at_[hidden]
> > wrote:
> > 
> > I suppose that would break cases like:
> > 
> > std::string getStr();
> > print(std::string_ref sr) { std::cout << sr << std::endl; }
> > 
> > print(getStr());
> > 
> > Causing people to have to write print(getStr().c_str()).
> 
> It's possible to add `string_ref(reference_wrapper<const std::string>)`
> constructor to allow people write `print(boost::cref(getStr()))` instead of
> `print(getStr().c_str())`.

boost::reference_wrapper will not construct from rvalues as of 1.56. 
std::reference_wrapper already doesn't. Even then, IMHO string_ref should not 
require these tricks, it should work transparently. I'm ok with leaving it 
vulnerable to incorrect use if it's not possible to protect it without 
sacrificing usability.