/usr/include/boost/hana/at.hpp is in libboost1.62-dev 1.62.0+dfsg-5.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 | /*!
@file
Defines `boost::hana::at` and `boost::hana::at_c`.
@copyright Louis Dionne 2013-2016
Distributed under the Boost Software License, Version 1.0.
(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
*/
#ifndef BOOST_HANA_AT_HPP
#define BOOST_HANA_AT_HPP
#include <boost/hana/fwd/at.hpp>
#include <boost/hana/concept/integral_constant.hpp>
#include <boost/hana/concept/iterable.hpp>
#include <boost/hana/config.hpp>
#include <boost/hana/core/dispatch.hpp>
#include <boost/hana/integral_constant.hpp>
#include <cstddef>
BOOST_HANA_NAMESPACE_BEGIN
//! @cond
template <typename Xs, typename N>
constexpr decltype(auto) at_t::operator()(Xs&& xs, N const& n) const {
using It = typename hana::tag_of<Xs>::type;
using At = BOOST_HANA_DISPATCH_IF(at_impl<It>,
hana::Iterable<It>::value
);
#ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
static_assert(hana::Iterable<It>::value,
"hana::at(xs, n) requires 'xs' to be an Iterable");
static_assert(hana::IntegralConstant<N>::value,
"hana::at(xs, n) requires 'n' to be an IntegralConstant");
#endif
return At::apply(static_cast<Xs&&>(xs), n);
}
//! @endcond
template <typename It, bool condition>
struct at_impl<It, when<condition>> : default_ {
template <typename ...Args>
static constexpr auto apply(Args&& ...) = delete;
};
template <std::size_t n, typename Xs>
constexpr decltype(auto) at_c(Xs&& xs) {
return hana::at(static_cast<Xs&&>(xs), hana::size_c<n>);
}
BOOST_HANA_NAMESPACE_END
#endif // !BOOST_HANA_AT_HPP
|