1349cc55cSDimitry Andric // -*- C++ -*- 2349cc55cSDimitry Andric //===----------------------------------------------------------------------===// 3349cc55cSDimitry Andric // 4349cc55cSDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5349cc55cSDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 6349cc55cSDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7349cc55cSDimitry Andric // 8349cc55cSDimitry Andric //===----------------------------------------------------------------------===// 9349cc55cSDimitry Andric 10349cc55cSDimitry Andric #ifndef _LIBCPP___RANGES_RANGE_ADAPTOR_H 11349cc55cSDimitry Andric #define _LIBCPP___RANGES_RANGE_ADAPTOR_H 12349cc55cSDimitry Andric 13bdd1243dSDimitry Andric #include <__concepts/constructible.h> 14bdd1243dSDimitry Andric #include <__concepts/derived_from.h> 15bdd1243dSDimitry Andric #include <__concepts/invocable.h> 16bdd1243dSDimitry Andric #include <__concepts/same_as.h> 17349cc55cSDimitry Andric #include <__config> 18349cc55cSDimitry Andric #include <__functional/compose.h> 19349cc55cSDimitry Andric #include <__functional/invoke.h> 20349cc55cSDimitry Andric #include <__ranges/concepts.h> 2106c3fb27SDimitry Andric #include <__type_traits/decay.h> 22*0fca6ea1SDimitry Andric #include <__type_traits/is_class.h> 2306c3fb27SDimitry Andric #include <__type_traits/is_nothrow_constructible.h> 2406c3fb27SDimitry Andric #include <__type_traits/remove_cvref.h> 25349cc55cSDimitry Andric #include <__utility/forward.h> 26349cc55cSDimitry Andric #include <__utility/move.h> 27349cc55cSDimitry Andric 28349cc55cSDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 29349cc55cSDimitry Andric # pragma GCC system_header 30349cc55cSDimitry Andric #endif 31349cc55cSDimitry Andric 3206c3fb27SDimitry Andric _LIBCPP_PUSH_MACROS 3306c3fb27SDimitry Andric #include <__undef_macros> 3406c3fb27SDimitry Andric 35349cc55cSDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 36349cc55cSDimitry Andric 3706c3fb27SDimitry Andric #if _LIBCPP_STD_VER >= 20 38349cc55cSDimitry Andric 39*0fca6ea1SDimitry Andric namespace ranges { 40*0fca6ea1SDimitry Andric 41349cc55cSDimitry Andric // CRTP base that one can derive from in order to be considered a range adaptor closure 42349cc55cSDimitry Andric // by the library. When deriving from this class, a pipe operator will be provided to 43349cc55cSDimitry Andric // make the following hold: 44349cc55cSDimitry Andric // - `x | f` is equivalent to `f(x)` 45349cc55cSDimitry Andric // - `f1 | f2` is an adaptor closure `g` such that `g(x)` is equivalent to `f2(f1(x))` 46349cc55cSDimitry Andric template <class _Tp> 47*0fca6ea1SDimitry Andric requires is_class_v<_Tp> && same_as<_Tp, remove_cv_t<_Tp>> 48349cc55cSDimitry Andric struct __range_adaptor_closure; 49349cc55cSDimitry Andric 50349cc55cSDimitry Andric // Type that wraps an arbitrary function object and makes it into a range adaptor closure, 51349cc55cSDimitry Andric // i.e. something that can be called via the `x | f` notation. 52349cc55cSDimitry Andric template <class _Fn> 53349cc55cSDimitry Andric struct __range_adaptor_closure_t : _Fn, __range_adaptor_closure<__range_adaptor_closure_t<_Fn>> { 5406c3fb27SDimitry Andric _LIBCPP_HIDE_FROM_ABI constexpr explicit __range_adaptor_closure_t(_Fn&& __f) : _Fn(std::move(__f)) {} 55349cc55cSDimitry Andric }; 56bdd1243dSDimitry Andric _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(__range_adaptor_closure_t); 57349cc55cSDimitry Andric 58349cc55cSDimitry Andric template <class _Tp> 59*0fca6ea1SDimitry Andric _Tp __derived_from_range_adaptor_closure(__range_adaptor_closure<_Tp>*); 60349cc55cSDimitry Andric 61349cc55cSDimitry Andric template <class _Tp> 62*0fca6ea1SDimitry Andric concept _RangeAdaptorClosure = !ranges::range<remove_cvref_t<_Tp>> && requires { 63*0fca6ea1SDimitry Andric // Ensure that `remove_cvref_t<_Tp>` is derived from `__range_adaptor_closure<remove_cvref_t<_Tp>>` and isn't derived 64*0fca6ea1SDimitry Andric // from `__range_adaptor_closure<U>` for any other type `U`. 65*0fca6ea1SDimitry Andric { ranges::__derived_from_range_adaptor_closure((remove_cvref_t<_Tp>*)nullptr) } -> same_as<remove_cvref_t<_Tp>>; 66*0fca6ea1SDimitry Andric }; 67*0fca6ea1SDimitry Andric 68*0fca6ea1SDimitry Andric template <ranges::range _Range, _RangeAdaptorClosure _Closure> 69*0fca6ea1SDimitry Andric requires invocable<_Closure, _Range> 70*0fca6ea1SDimitry Andric [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) 71*0fca6ea1SDimitry Andric operator|(_Range&& __range, _Closure&& __closure) noexcept(is_nothrow_invocable_v<_Closure, _Range>) { 72*0fca6ea1SDimitry Andric return std::invoke(std::forward<_Closure>(__closure), std::forward<_Range>(__range)); 73cb14a3feSDimitry Andric } 74349cc55cSDimitry Andric 75349cc55cSDimitry Andric template <_RangeAdaptorClosure _Closure, _RangeAdaptorClosure _OtherClosure> 76*0fca6ea1SDimitry Andric requires constructible_from<decay_t<_Closure>, _Closure> && constructible_from<decay_t<_OtherClosure>, _OtherClosure> 77*0fca6ea1SDimitry Andric [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator|(_Closure&& __c1, _OtherClosure&& __c2) noexcept( 78cb14a3feSDimitry Andric is_nothrow_constructible_v<decay_t<_Closure>, _Closure> && 79cb14a3feSDimitry Andric is_nothrow_constructible_v<decay_t<_OtherClosure>, _OtherClosure>) { 80cb14a3feSDimitry Andric return __range_adaptor_closure_t(std::__compose(std::forward<_OtherClosure>(__c2), std::forward<_Closure>(__c1))); 81cb14a3feSDimitry Andric } 82*0fca6ea1SDimitry Andric 83*0fca6ea1SDimitry Andric template <class _Tp> 84*0fca6ea1SDimitry Andric requires is_class_v<_Tp> && same_as<_Tp, remove_cv_t<_Tp>> 85*0fca6ea1SDimitry Andric struct __range_adaptor_closure {}; 86*0fca6ea1SDimitry Andric 87*0fca6ea1SDimitry Andric # if _LIBCPP_STD_VER >= 23 88*0fca6ea1SDimitry Andric template <class _Tp> 89*0fca6ea1SDimitry Andric requires is_class_v<_Tp> && same_as<_Tp, remove_cv_t<_Tp>> 90*0fca6ea1SDimitry Andric class range_adaptor_closure : public __range_adaptor_closure<_Tp> {}; 91*0fca6ea1SDimitry Andric # endif // _LIBCPP_STD_VER >= 23 92*0fca6ea1SDimitry Andric 93*0fca6ea1SDimitry Andric } // namespace ranges 94349cc55cSDimitry Andric 9506c3fb27SDimitry Andric #endif // _LIBCPP_STD_VER >= 20 96349cc55cSDimitry Andric 97349cc55cSDimitry Andric _LIBCPP_END_NAMESPACE_STD 98349cc55cSDimitry Andric 9906c3fb27SDimitry Andric _LIBCPP_POP_MACROS 10006c3fb27SDimitry Andric 101349cc55cSDimitry Andric #endif // _LIBCPP___RANGES_RANGE_ADAPTOR_H 102