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88 lines
2.0 KiB
C++
88 lines
2.0 KiB
C++
/*=============================================================================
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Copyright (c) 2014 Paul Fultz II
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indirect.h
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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==============================================================================*/
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#ifndef FIT_GUARD_FUNCTION_INDIRECT_H
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#define FIT_GUARD_FUNCTION_INDIRECT_H
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/// indirect
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/// ========
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///
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/// Description
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/// -----------
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///
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/// The `indirect` function adaptor dereferences the object before calling it.
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///
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/// Synopsis
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/// --------
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///
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/// template<class F>
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/// constexpr indirect_adaptor<F> indirect(F f);
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///
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/// Requirements
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/// ------------
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///
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/// F must be:
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///
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/// FunctionObject
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/// MoveConstructible
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/// Dereferenceable
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///
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/// Example
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/// -------
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///
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/// struct sum
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/// {
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/// template<class T, class U>
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/// T operator()(T x, U y) const
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/// {
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/// return x+y;
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/// }
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/// };
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///
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/// int r = indirect(std::make_unique<sum>())(3,2);
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/// assert(r == 5);
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///
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#include <fit/detail/delegate.h>
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#include <fit/returns.h>
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#include <fit/reveal.h>
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#include <fit/always.h>
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#include <fit/detail/move.h>
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#include <fit/detail/make.h>
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#include <fit/detail/static_const_var.h>
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namespace fit {
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template<class F>
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struct indirect_adaptor : F
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{
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FIT_INHERIT_CONSTRUCTOR(indirect_adaptor, F);
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template<class... Ts>
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constexpr const F& base_function(Ts&&... xs) const
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{
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return always_ref(*this)(xs...);
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}
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struct failure
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: failure_for<decltype(*std::declval<F>())>
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{};
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FIT_RETURNS_CLASS(indirect_adaptor);
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template<class... Ts>
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constexpr auto operator()(Ts&&... xs) const FIT_RETURNS
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(
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(*FIT_MANGLE_CAST(const F&)(FIT_CONST_THIS->base_function(xs...)))(fit::forward<Ts>(xs)...)
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);
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};
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FIT_DECLARE_STATIC_VAR(indirect, detail::make<indirect_adaptor>);
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}
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#endif |