Re: [boost] [operators] A modern SFINAE-based version of boost::operators?

Subject: Re: [boost] [operators] A modern SFINAE-based version of boost::operators?
From: Richard Hodges (hodges.r_at_[hidden])
Date: 2017-11-13 15:05:49

of course I mean:

Foo operator+(Foo l, Foo const& r) { return l += r; return l; }

in the second version.

On 13 November 2017 at 16:05, Richard Hodges <hodges.r_at_[hidden]> wrote:

> I for one would be grateful for work on this. Particularly if it also
> automatically manufactures move-aware versions of binary operators.
>
> eg:
>
> Foo&& operator+(Foo&& l, Foo const& r) { return std::move(l += r); }
> Foo operator+(Foo const& l, Foo const& r) { return l += r; return l; }
>
>
>
> On 13 November 2017 at 15:20, Beman Dawes via Boost <boost_at_[hidden]
> > wrote:
>
>> Peter Sommerlad, committee member and C++Now presenter who often proposes
>> additions to fill in  holes in the standard library, asked me:
>>
>> Are you aware of anybody who tried to provide a boost::operators style of
>> automatically providing additional operators with a single base class that
>> through SFINAE injects all possible operators based on the ones defined in
>> the template parameter? This won't give you the control of the current
>> boost::operators, but would be much easier to teach.
>>
>> For example
>>
>> struct Me : make_operators_for<Me>{
>> Me& operator+=(Me const&);       // You get +
>> bool operator<(Me const&) const; // You get all relops (<=> will make that
>> obsolete)
>> Me& operator++();                // you get postfix
>> //etc.
>> };
>>
>> Today we have the facilities and compilers to make that happen.
>>
>> What do you think? Who should I ask?
>>
>> Anyone doing any work on operators or have any thoughts about updating
>> boost::operators?
>>
>> --Beman
>>
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>
>