Re: [boost] [hash] Extract module from functional + std::hash_combine

Subject: Re: [boost] [hash] Extract module from functional + std::hash_combine
From: Richard Hodges (hodges.r_at_[hidden])
Date: 2017-12-19 15:23:05

> The C++11 std::hash was specified before boost::hash was created, so...

source :
https://github.com/boostorg/functional/blob/develop/include/boost/functional/hash/hash.hpp

// Copyright 2005-2014 Daniel James.
// Distributed under the Boost Software License, Version 1.0. (See
accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

You're saying that the c++11 standard codified std::hash in 2005? This
seems to me to be an extraordinary claim.

More likely is that std::hash is the retarded cousin of boost::hash, and
the c++11 committee's gravest error.

On 19 December 2017 at 15:51, Daniel James via Boost <boost_at_[hidden]>
wrote:

> On 19 December 2017 at 14:12, Richard Hodges via Boost
> <boost_at_[hidden]> wrote:
> >
> > Whoever decided to downgrade boost hash before solidifying its
> uselessness
> > in the c++11 standard?
>
> The C++11 std::hash was specified before boost::hash was created, so
> it wasn't downgraded. There have been several proposals for improving
> std::hash, some of which do have advantages over `boost::hash`, but
> the standards committee hasn't settled on any of them. But it's
> possible that the next standard will include 'hash_combine', as well
> as functions using variadic arguments:
>
> http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n3876.pdf
>
> This is a bit of a compromise that makes it easier to implement custom
> hash functions but doesn't prevent any of the other proposal from
> going forward. I was thinking about implementing the variadic
> functions in that paper for 1.67.0, but I think I'll wait to see if
> it's added to the standard.
>
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