GCC Code Coverage Report

Directory: include/kumi/
File: include/kumi/algorithm/back_front.hpp
Date: 2026-10-14 16:33:56
Exec Total Coverage
Lines: 4 4 100.0%
Functions: 0 0 -%
Branches: 0 0 -%
Line Branch Exec Source
1 //======================================================================================================================
2 /*
3 KUMI - Compact Tuple Tools
4 Copyright : KUMI Project Contributors
5 SPDX-License-Identifier: BSL-1.0
6 */
7 //======================================================================================================================
8 #pragma once
9
10 namespace kumi
11 {
12 struct front_t
13 {
14 template<kumi::concepts::non_empty_product_type T>
15 [[nodiscard]] KUMI_ABI constexpr decltype(auto) operator()(T&& t) const
16 {
17 26 if constexpr (kumi::concepts::record_type<T>) return (*this)(kumi::values_of(KUMI_FWD(t)));
18 36 else return get<0>(KUMI_FWD(t));
19 }
20 };
21
22 struct back_t
23 {
24 template<kumi::concepts::non_empty_product_type T>
25 [[nodiscard]] KUMI_ABI constexpr decltype(auto) operator()(T&& t) const
26 {
27 26 if constexpr (kumi::concepts::record_type<T>) return (*this)(kumi::values_of(KUMI_FWD(t)));
28 36 else return get<kumi::size_v<T> - 1>(KUMI_FWD(t));
29 }
30 };
31
32 //====================================================================================================================
33 /**
34 @ingroup kumi_queries
35
36 @var front
37 @brief Callable object used to retrieve the front of a product type
38
39 @note This function does not take part in overload resolution if t is an empty product type.
40
41 @qualifier nodiscard
42 @qualifier inline
43 @qualifier constexpr
44
45 @groupheader{Header file}
46 @code
47 #include <kumi/algorithm/back_front.hpp>
48 @endcode
49
50 @groupheader{Call Signature}
51
52 @code
53 template<product_type T>
54 [[nodiscard]] constexpr decltype(auto) front(T && t);
55 @endcode
56
57 @subgroupheader{Parameters}
58
59 - `t`: Product Type to access
60
61 @subgroupheader{Return value}
62
63 - A reference to the first element of the product type `t`.
64
65 @groupheader{Helper type}
66
67 @snippet include/kumi/algorithm/back_front.hpp front_t
68
69 Computes the return type of a call to kumi::front
70
71 @groupheader{Examples}
72
73 @tab_begin
74
75 @tab{Tuple}
76 @godbolt{doc/tuple/algo/back-front.cpp}
77
78 @tab{Record}
79 @godbolt{doc/record/algo/back-front.cpp}
80
81 @tab_end
82 **/
83 //====================================================================================================================
84 KUMI_VARIABLE_ABI constexpr front_t front{};
85
86 //====================================================================================================================
87 /**
88 @ingroup kumi_queries
89
90 @var back
91 @brief Callable object used to retrieve the back of a product type
92
93 @note This function does not take part in overload resolution if t is an empty product type.
94
95 @qualifier nodiscard
96 @qualifier inline
97 @qualifier constexpr
98
99 @groupheader{Header file}
100 @code
101 #include <kumi/algorithm/back_front.hpp>
102 @endcode
103
104 @groupheader{Call Signature}
105
106 @code
107 template<product_type T>
108 [[nodiscard]] constexpr decltype(auto) back(T && t);
109 @endcode
110
111 @subgroupheader{Parameters}
112
113 - `t`: Product Type to access
114
115 @subgroupheader{Return value}
116
117 - A reference to the last element of the product type `t`.
118
119 @groupheader{Helper type}
120
121 @snippet include/kumi/algorithm/back_front.hpp back_t
122
123 Computes the return type of a call to kumi::back
124
125 @groupheader{Examples}
126
127 @tab_begin
128
129 @tab{Tuple}
130 @godbolt{doc/tuple/algo/back-front.cpp}
131
132 @tab{Record}
133 @godbolt{doc/record/algo/back-front.cpp}
134
135 @tab_end
136 **/
137 //====================================================================================================================
138 KUMI_VARIABLE_ABI constexpr back_t back{};
139
140 namespace result
141 {
142 //! [front_t]
143 template<kumi::concepts::product_type T> using front_t = kumi::stored_member_t<0, T>;
144
145 template<kumi::concepts::product_type T> struct front
146 {
147 using type = kumi::result::front_t<T>;
148 };
149
150 //! [front_t]
151
152 //! [back_t]
153 template<kumi::concepts::product_type T> using back_t = kumi::stored_member_t<kumi::size_v<T> - 1, T>;
154
155 template<kumi::concepts::product_type T> struct back
156 {
157 using type = kumi::result::back_t<T>;
158 };
159
160 //! [back_t]
161 }
162 }
163