Re: [boost] [Fit] upcoming formal review for Boost.Fit

Subject: Re: [boost] [Fit] upcoming formal review for Boost.Fit
From: Sam Kellett (samkellett_at_[hidden])
Date: 2016-03-03 13:36:23

On 3 March 2016 at 17:39, paul Fultz <pfultz2_at_[hidden]> wrote:

>
>
>
>
>
> > On Wednesday, March 2, 2016 2:56 PM, Bjorn Reese <
> breese_at_[hidden]> wrote:
> > > On 02/27/2016 05:16 PM, Vicente J. Botet Escriba wrote:
> >
> >>  Documentation:http://pfultz2.github.io/Fit/doc/html/
> >
> > In More Examples / Projections there is this example:
> >
> >    std::sort(std::begin(people), std::end(people),
> >              by(&Person::year_of_birth, _ < _));
> >
> > That strikes me as a very terse syntax, where the reader could easily
> > miss the fact that two values are being compared. Have you considered
>
> > the use of placeholders like _1 and _2 instead?
>
> They are already supported. The anonymous placeholders are only there to
> describe an operator(they are not bind expressions). It could also be
> written
> like this as well:
>
> std::sort(std::begin(people), std::end(people),
> by(&Person::year_of_birth, std::less_than<>()));
>
> The clarity of two parameters being passed to `std::less_than` is just as
> clear as when using the anonymous placeholders. The advantage of writing
>
> `_ < _` is that it is generic, SFINAE and constexpr friendly.
>

so if i understand correctly, that means that this work:

std::sort(std::begin(people), std::end(people), by(&Person::year_of_birth,
_2 < _1);

as one way to reverse sort. right?