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69 lines
2.0 KiB
C++
69 lines
2.0 KiB
C++
/*=============================================================================
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Copyright (c) 2014 Paul Fultz II
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function.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_FUNCTION_H
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#define FIT_GUARD_FUNCTION_FUNCTION_H
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/// FIT_STATIC_FUNCTION
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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 `FIT_STATIC_FUNCTION` macro allows initializing a function object from a
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/// `constexpr` expression. It also ensures that the function object will have a
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/// unique address across translation units. This helps to avoid ODR violations.
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///
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/// Example
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/// -------
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///
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/// FIT_STATIC_FUNCTION(sum) = fit::partial([](int x, int y)
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/// {
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/// return x + y;
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/// });
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///
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#include <fit/reveal.h>
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#include <fit/detail/static_constexpr.h>
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#include <fit/detail/static_const_var.h>
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#include <fit/detail/constexpr_deduce.h>
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namespace fit {
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namespace detail {
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struct reveal_static_const_factory
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{
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constexpr reveal_static_const_factory()
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{}
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#if FIT_NO_UNIQUE_STATIC_VAR
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template<class F>
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constexpr reveal_adaptor<F> operator=(const F& f) const
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{
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static_assert(is_default_constructible<F>::value, "Static functions must be default constructible");
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return reveal_adaptor<F>(f);
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}
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#else
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template<class F>
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constexpr const reveal_adaptor<F>& operator=(const F&) const
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{
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static_assert(is_default_constructible<F>::value, "Static functions must be default constructible");
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return static_const_var<reveal_adaptor<F>>();
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}
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#endif
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};
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}}
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#if FIT_NO_UNIQUE_STATIC_VAR
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#define FIT_STATIC_FUNCTION(name) FIT_STATIC_CONSTEXPR auto name = FIT_DETAIL_MSVC_CONSTEXPR_DEDUCE fit::detail::reveal_static_const_factory()
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#else
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#define FIT_STATIC_FUNCTION(name) FIT_STATIC_AUTO_REF name = fit::detail::reveal_static_const_factory()
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#endif
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#endif
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