Re: [boost] Variadic append for std::string

3 Jan 2017


      On Thu, Dec 29, 2016 at 1:19 AM, Yakov Galka  wrote:
...
On Tue, Dec 27, 2016 at 4:47 PM, Olaf van der Spek  wrote:
...
One frequently needs to append stuff to strings, but the standard way
(s += "A" + "B" + to_string(42)) isn't optimal due to temporaries.
Can't we already write it through (((s += "A") += "B") += to_string(42))?
This is the time I think that assignment operators, other than =, should
have had left associativitiy... pity they don't.
<< does the trick:

s << "A" << "B" << 42;

std::string& operator<<(std::string& os, std::string_view v)
{
    return os += v;
}

std::string& operator<<(std::string& os, long long v)
{
    return os += std::to_string(v);
}


-- 
Olaf