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 15:05:13

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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