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
11// constexpr iterator<false> begin();
12// constexpr iterator<true> begin() const
13// requires range<const V> &&
14// regular_invocable<const F&, range_reference_t<const V>>;
15
16#include <ranges>
17
18#include "test_macros.h"
19#include "types.h"
20
21template<class T>
22concept BeginInvocable = requires(T t) { t.begin(); };
23
24constexpr bool test() {
25 int buff[8] = {0, 1, 2, 3, 4, 5, 6, 7};
26
27 {
28 std::ranges::transform_view transformView(MoveOnlyView{buff}, PlusOneMutable{});
29 assert(transformView.begin().base() == buff);
30 assert(*transformView.begin() == 1);
31 }
32
33 {
34 std::ranges::transform_view transformView(ForwardView{buff}, PlusOneMutable{});
35 assert(base(transformView.begin().base()) == buff);
36 assert(*transformView.begin() == 1);
37 }
38
39 {
40 std::ranges::transform_view transformView(InputView{buff}, PlusOneMutable{});
41 assert(base(transformView.begin().base()) == buff);
42 assert(*transformView.begin() == 1);
43 }
44
45 {
46 const std::ranges::transform_view transformView(MoveOnlyView{buff}, PlusOne{});
47 assert(*transformView.begin() == 1);
48 }
49
50 static_assert(!BeginInvocable<const std::ranges::transform_view<MoveOnlyView, PlusOneMutable>>);
51
52 return true;
53}
54
55int main(int, char**) {
56 test();
57 static_assert(test());
58
59 return 0;
60}
61

source code of libcxx/test/std/ranges/range.adaptors/range.transform/begin.pass.cpp