1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 // UNSUPPORTED: c++03, c++11, c++14, c++17
10 // UNSUPPORTED: libcpp-has-no-incomplete-ranges
11
12 // std::views::lazy_split
13
14 #include <ranges>
15
16 #include <array>
17 #include <cassert>
18 #include <concepts>
19 #include <string_view>
20 #include <utility>
21
22 #include "test_iterators.h"
23 #include "types.h"
24
25 template <class View, class T>
26 concept CanBePiped = requires (View&& view, T&& t) {
27 { std::forward<View>(view) | std::forward<T>(t) };
28 };
29
30 struct SomeView : std::ranges::view_base {
31 const std::string_view* v_;
SomeViewSomeView32 constexpr SomeView(const std::string_view& v) : v_(&v) {}
beginSomeView33 constexpr auto begin() const { return v_->begin(); }
endSomeView34 constexpr auto end() const { return v_->end(); }
35 };
36
37 struct NotAView { };
38
39 static_assert(!std::is_invocable_v<decltype(std::views::lazy_split)>);
40 static_assert(!std::is_invocable_v<decltype(std::views::lazy_split), SomeView, NotAView>);
41 static_assert(!std::is_invocable_v<decltype(std::views::lazy_split), NotAView, SomeView>);
42 static_assert( std::is_invocable_v<decltype(std::views::lazy_split), SomeView, SomeView>);
43
44 static_assert( CanBePiped<SomeView&, decltype(std::views::lazy_split)>);
45 static_assert( CanBePiped<char(&)[10], decltype(std::views::lazy_split)>);
46 static_assert(!CanBePiped<char(&&)[10], decltype(std::views::lazy_split)>);
47 static_assert(!CanBePiped<NotAView, decltype(std::views::lazy_split)>);
48
49 static_assert(std::same_as<decltype(std::views::lazy_split), decltype(std::ranges::views::lazy_split)>);
50
test()51 constexpr bool test() {
52 std::string_view input = "abc";
53 std::string_view sep = "a";
54
55 // Test that `std::views::lazy_split` is a range adaptor.
56
57 // Test `views::lazy_split(input, sep)`.
58 {
59 SomeView view(input);
60
61 using Result = std::ranges::lazy_split_view<SomeView, std::string_view>;
62 std::same_as<Result> decltype(auto) result = std::views::lazy_split(view, sep);
63 assert(result.base().begin() == input.begin());
64 assert(result.base().end() == input.end());
65 }
66
67 // Test `views::lazy_split(sep)(input)`.
68 {
69 SomeView view(input);
70
71 using Result = std::ranges::lazy_split_view<SomeView, std::string_view>;
72 std::same_as<Result> decltype(auto) result = std::views::lazy_split(sep)(view);
73 assert(result.base().begin() == input.begin());
74 assert(result.base().end() == input.end());
75 }
76
77 // Test `view | views::lazy_split`.
78 {
79 SomeView view(input);
80
81 using Result = std::ranges::lazy_split_view<SomeView, std::string_view>;
82 std::same_as<Result> decltype(auto) result = view | std::views::lazy_split(sep);
83 assert(result.base().begin() == input.begin());
84 assert(result.base().end() == input.end());
85 }
86
87 // Test `adaptor | views::lazy_split`.
88 {
89 SomeView view(input);
90 auto f = [](char c) { return c; };
91 auto partial = std::views::transform(f) | std::views::lazy_split(sep);
92
93 using Result = std::ranges::lazy_split_view<std::ranges::transform_view<SomeView, decltype(f)>, std::string_view>;
94 std::same_as<Result> decltype(auto) result = partial(view);
95 assert(result.base().base().begin() == input.begin());
96 assert(result.base().base().end() == input.end());
97 }
98
99 // Test `views::lazy_split | adaptor`.
100 {
101 SomeView view(input);
102 auto f = [](auto v) { return v; };
103 auto partial = std::views::lazy_split(sep) | std::views::transform(f);
104
105 using Result = std::ranges::transform_view<std::ranges::lazy_split_view<SomeView, std::string_view>, decltype(f)>;
106 std::same_as<Result> decltype(auto) result = partial(view);
107 assert(result.base().base().begin() == input.begin());
108 assert(result.base().base().end() == input.end());
109 }
110
111 // Test that one can call `std::views::lazy_split` with arbitrary stuff, as long as we
112 // don't try to actually complete the call by passing it a range.
113 //
114 // That makes no sense and we can't do anything with the result, but it's valid.
115 {
116 struct X { };
117 [[maybe_unused]] auto partial = std::views::lazy_split(X{});
118 }
119
120 return true;
121 }
122
main(int,char **)123 int main(int, char**) {
124 test();
125 static_assert(test());
126
127 return 0;
128 }
129