Edit: /usr/include/boost/hof/indirect.hpp (3268B)
/*=============================================================================
Copyright (c) 2014 Paul Fultz II
indirect.h
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)
==============================================================================*/
#ifndef BOOST_HOF_GUARD_FUNCTION_INDIRECT_H
#define BOOST_HOF_GUARD_FUNCTION_INDIRECT_H
/// indirect
/// ========
///
/// Description
/// -----------
///
/// The `indirect` function adaptor dereferences the object before calling it.
///
/// Synopsis
/// --------
///
/// template
/// constexpr indirect_adaptor indirect(F f);
///
/// Semantics
/// ---------
///
/// assert(indirect(f)(xs...) == (*f)(xs...));
///
/// Requirements
/// ------------
///
/// F must be:
///
/// * MoveConstructible
/// * Dereferenceable
///
/// Example
/// -------
///
/// #include
/// #include
/// #include
/// using namespace boost::hof;
///
/// struct sum
/// {
/// template
/// T operator()(T x, U y) const
/// {
/// return x+y;
/// }
/// };
///
/// int main() {
/// int r = indirect(std::make_unique())(3,2);
/// assert(r == 5);
/// }
///
#include
#include
#include
#include
#include
#include
#include
namespace boost { namespace hof {
// TODO: Support non-classes as well
template
struct indirect_adaptor : F
{
typedef indirect_adaptor fit_rewritable1_tag;
BOOST_HOF_INHERIT_CONSTRUCTOR(indirect_adaptor, F);
template
constexpr const F& base_function(Ts&&... xs) const noexcept
{
return boost::hof::always_ref(*this)(xs...);
}
struct failure
: failure_for())>
{};
BOOST_HOF_RETURNS_CLASS(indirect_adaptor);
template
constexpr BOOST_HOF_SFINAE_RESULT(decltype(*std::declval()), id_...)
operator()(Ts&&... xs) const BOOST_HOF_SFINAE_RETURNS
(
(*BOOST_HOF_MANGLE_CAST(const F&)(BOOST_HOF_CONST_THIS->base_function(xs...)))(BOOST_HOF_FORWARD(Ts)(xs)...)
);
};
template
struct indirect_adaptor
{
typedef indirect_adaptor fit_rewritable1_tag;
F* f;
constexpr indirect_adaptor() noexcept
{}
constexpr indirect_adaptor(F* x) noexcept
: f(x)
{}
template
constexpr F& base_function(Ts&&...) const noexcept
{
return *f;
}
struct failure
: failure_for
{};
BOOST_HOF_RETURNS_CLASS(indirect_adaptor);
template
constexpr BOOST_HOF_SFINAE_RESULT(F, id_...)
operator()(Ts&&... xs) const BOOST_HOF_SFINAE_RETURNS
(
(BOOST_HOF_MANGLE_CAST(F&)(BOOST_HOF_CONST_THIS->base_function(xs...)))(BOOST_HOF_FORWARD(Ts)(xs)...)
);
};
BOOST_HOF_DECLARE_STATIC_VAR(indirect, detail::make);
}} // namespace boost::hof
#endif