forked from boostorg/mp11
51 lines
2.2 KiB
Plaintext
51 lines
2.2 KiB
Plaintext
////
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Copyright 2017 Peter Dimov
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Distributed under the Boost Software License, Version 1.0.
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See accompanying file LICENSE_1_0.txt or copy at
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http://www.boost.org/LICENSE_1_0.txt
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////
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[#tuple]
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# Tuple Operations, <boost/mp11/tuple.hpp>
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:toc:
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:toc-title:
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:idprefix:
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## tuple_apply(f, tp)
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template<class F, class Tp> constexpr /*...*/ tuple_apply(F&& f, Tp&& tp);
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`tuple_apply(f, tp)` returns `std::forward<F>(f)(std::get<J>(std::forward<Tp>(tp))...)` for `J` in 0..`N-1`,
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where `N` is `std::tuple_size<typename std::remove_reference<Tp>::type>::value`. Same as `std::apply` in C++17.
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## construct_from_tuple<T>(tp)
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template<class T, class Tp> T construct_from_tuple(Tp&& tp);
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`construct_from_tuple<T>(tp)` returns `T(std::get<J>(std::forward<Tp>(tp))...)` for `J` in 0..`N-1`,
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where `N` is `std::tuple_size<typename std::remove_reference<Tp>::type>::value`. Same as `std::make_from_tuple` in {cpp}17.
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The name of the function doesn't match the {cpp}17 one to avoid ambiguities when both are visible or in unqualified calls.
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## tuple_for_each(tp, f)
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template<class Tp, class F> constexpr F tuple_for_each(Tp&& tp, F&& f);
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`tuple_for_each(tp, f)` applies the function object `f` to each element of `tp` by evaluating the
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expression `f(std::get<J>(std::forward<Tp>(tp)))` for `J` in 0..`N-1`, where `N` is `std::tuple_size<typename std::remove_reference<Tp>::type>::value`.
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Returns `std::forward<F>(f)`.
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## tuple_transform(f, tp)
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template<class F, class... Tps> constexpr /*...*/ tuple_transform(F const& f, Tps const&... tps);
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`tuple_transform(f, tps...)` accepts a function object `f` followed by one or more tuples of equal length
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(`std::pair` is also accepted). The callable `f` must accept as many arguments as there are tuples. The
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function object is called with the first elements of each tuple, then with the second element of each tuple,
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and so on, by evaluating the expression `f(std::get<J>(tps)...)` for `J` in 0..`N-1`, where `N` is
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`std::tuple_size<Tp>::value` for the first tuple `Tp`. The results are returned as a `Tp<Ts...>` with `Ts...`
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deduced from the return values of `f`. Warning: The order in which the elements of the tuples are processed
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is undefined. Calling `f` should not have side-effects.
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