detail/variadic/foldl1.hpp

0001 /*!
0002 @file
0003 Defines `boost::hana::detail::variadic::foldl1`.
0004
0005 Copyright Louis Dionne 2013-2022
0006 Distributed under the Boost Software License, Version 1.0.
0007 (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
0008  */
0009
0010 #ifndef BOOST_HANA_DETAIL_VARIADIC_FOLDL1_HPP
0011 #define BOOST_HANA_DETAIL_VARIADIC_FOLDL1_HPP
0012
0013 #include <boost/hana/config.hpp>
0014 #include <boost/hana/core/when.hpp>
0015
0016
0017 namespace boost { namespace hana { namespace detail { namespace variadic {
0018     //! @cond
0019     template <unsigned int n, typename = when<true>>
0020     struct foldl1_impl;
0021
0022     template <>
0023     struct foldl1_impl<1> {
0024         template <typename F, typename X1>
0025         static constexpr X1 apply(F&&, X1&& x1)
0026         { return static_cast<X1&&>(x1); }
0027     };
0028
0029     template <>
0030     struct foldl1_impl<2> {
0031         template <typename F, typename X1, typename X2>
0032         static constexpr decltype(auto) apply(F&& f, X1&& x1, X2&& x2) {
0033             return static_cast<F&&>(f)(static_cast<X1&&>(x1),
0034                                        static_cast<X2&&>(x2));
0035         }
0036     };
0037
0038     template <>
0039     struct foldl1_impl<3> {
0040         template <typename F, typename X1, typename X2, typename X3>
0041         static constexpr decltype(auto) apply(F&& f, X1&& x1, X2&& x2, X3&& x3) {
0042             return f(f(static_cast<X1&&>(x1),
0043                        static_cast<X2&&>(x2)),
0044                        static_cast<X3&&>(x3));
0045         }
0046     };
0047
0048     template <>
0049     struct foldl1_impl<4> {
0050         template <typename F, typename X1, typename X2, typename X3, typename X4>
0051         static constexpr decltype(auto) apply(F&& f, X1&& x1, X2&& x2, X3&& x3, X4&& x4) {
0052             return f(f(f(static_cast<X1&&>(x1),
0053                          static_cast<X2&&>(x2)),
0054                          static_cast<X3&&>(x3)),
0055                          static_cast<X4&&>(x4));
0056         }
0057     };
0058
0059     template <>
0060     struct foldl1_impl<5> {
0061         template <typename F, typename X1, typename X2, typename X3, typename X4, typename X5>
0062         static constexpr decltype(auto) apply(F&& f, X1&& x1, X2&& x2, X3&& x3, X4&& x4, X5&& x5) {
0063             return f(f(f(f(static_cast<X1&&>(x1),
0064                            static_cast<X2&&>(x2)),
0065                            static_cast<X3&&>(x3)),
0066                            static_cast<X4&&>(x4)),
0067                            static_cast<X5&&>(x5));
0068         }
0069     };
0070
0071     template <>
0072     struct foldl1_impl<6> {
0073         template <typename F, typename X1, typename X2, typename X3, typename X4, typename X5, typename X6>
0074         static constexpr decltype(auto) apply(F&& f, X1&& x1, X2&& x2, X3&& x3, X4&& x4, X5&& x5, X6&& x6) {
0075             return f(f(f(f(f(static_cast<X1&&>(x1),
0076                              static_cast<X2&&>(x2)),
0077                              static_cast<X3&&>(x3)),
0078                              static_cast<X4&&>(x4)),
0079                              static_cast<X5&&>(x5)),
0080                              static_cast<X6&&>(x6));
0081         }
0082     };
0083
0084     template <unsigned int n>
0085     struct foldl1_impl<n, when<(n >= 7) && (n < 14)>> {
0086         template <typename F, typename X1, typename X2, typename X3, typename X4, typename X5, typename X6, typename X7, typename ...Xn>
0087         static constexpr decltype(auto)
0088         apply(F&& f
0089               , X1&& x1, X2&& x2, X3&& x3, X4&& x4, X5&& x5, X6&& x6, X7&& x7
0090               , Xn&& ...xn)
0091         {
0092             return foldl1_impl<sizeof...(xn) + 1>::apply(
0093                 f,
0094                 f(f(f(f(f(f(static_cast<X1&&>(x1),
0095                             static_cast<X2&&>(x2)),
0096                             static_cast<X3&&>(x3)),
0097                             static_cast<X4&&>(x4)),
0098                             static_cast<X5&&>(x5)),
0099                             static_cast<X6&&>(x6)),
0100                             static_cast<X7&&>(x7)),
0101                 static_cast<Xn&&>(xn)...
0102             );
0103         }
0104     };
0105
0106     template <unsigned int n>
0107     struct foldl1_impl<n, when<(n >= 14) && (n < 28)>> {
0108         template <
0109               typename F
0110             , typename X1, typename X2, typename X3,  typename X4,  typename X5,  typename X6,  typename X7
0111             , typename X8, typename X9, typename X10, typename X11, typename X12, typename X13, typename X14
0112             , typename ...Xn
0113         >
0114         static constexpr decltype(auto)
0115         apply(F&& f
0116               , X1&& x1, X2&& x2, X3&& x3,   X4&& x4,   X5&& x5,   X6&& x6,   X7&& x7
0117               , X8&& x8, X9&& x9, X10&& x10, X11&& x11, X12&& x12, X13&& x13, X14&& x14
0118               , Xn&& ...xn)
0119         {
0120             return foldl1_impl<sizeof...(xn) + 1>::apply(
0121                 f,
0122                 f(f(f(f(f(f(f(f(f(f(f(f(f(
0123                     static_cast<X1&&>(x1),  static_cast<X2&&>(x2)), static_cast<X3&&>(x3)),   static_cast<X4&&>(x4)),   static_cast<X5&&>(x5)),   static_cast<X6&&>(x6)),   static_cast<X7&&>(x7)),
0124                     static_cast<X8&&>(x8)), static_cast<X9&&>(x9)), static_cast<X10&&>(x10)), static_cast<X11&&>(x11)), static_cast<X12&&>(x12)), static_cast<X13&&>(x13)), static_cast<X14&&>(x14))
0125                 , static_cast<Xn&&>(xn)...);
0126
0127         }
0128     };
0129
0130     template <unsigned int n>
0131     struct foldl1_impl<n, when<(n >= 28) && (n < 56)>> {
0132         template <
0133               typename F
0134             , typename X1,  typename X2,  typename X3,  typename X4,  typename X5,  typename X6,  typename X7
0135             , typename X8,  typename X9,  typename X10, typename X11, typename X12, typename X13, typename X14
0136             , typename X15, typename X16, typename X17, typename X18, typename X19, typename X20, typename X21
0137             , typename X22, typename X23, typename X24, typename X25, typename X26, typename X27, typename X28
0138             , typename ...Xn
0139         >
0140         static constexpr decltype(auto)
0141         apply(F&& f
0142               , X1&& x1,   X2&& x2,   X3&& x3,   X4&& x4,   X5&& x5,   X6&& x6,   X7&& x7
0143               , X8&& x8,   X9&& x9,   X10&& x10, X11&& x11, X12&& x12, X13&& x13, X14&& x14
0144               , X15&& x15, X16&& x16, X17&& x17, X18&& x18, X19&& x19, X20&& x20, X21&& x21
0145               , X22&& x22, X23&& x23, X24&& x24, X25&& x25, X26&& x26, X27&& x27, X28&& x28
0146               , Xn&& ...xn)
0147         {
0148             return foldl1_impl<sizeof...(xn) + 1>::apply(
0149                 f,
0150                 f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(
0151                     static_cast<X1&&>(x1),    static_cast<X2&&>(x2)),   static_cast<X3&&>(x3)),   static_cast<X4&&>(x4)),   static_cast<X5&&>(x5)),   static_cast<X6&&>(x6)),   static_cast<X7&&>(x7)),
0152                     static_cast<X8&&>(x8)),   static_cast<X9&&>(x9)),   static_cast<X10&&>(x10)), static_cast<X11&&>(x11)), static_cast<X12&&>(x12)), static_cast<X13&&>(x13)), static_cast<X14&&>(x14)),
0153                     static_cast<X15&&>(x15)), static_cast<X16&&>(x16)), static_cast<X17&&>(x17)), static_cast<X18&&>(x18)), static_cast<X19&&>(x19)), static_cast<X20&&>(x20)), static_cast<X21&&>(x21)),
0154                     static_cast<X22&&>(x22)), static_cast<X23&&>(x23)), static_cast<X24&&>(x24)), static_cast<X25&&>(x25)), static_cast<X26&&>(x26)), static_cast<X27&&>(x27)), static_cast<X28&&>(x28))
0155                 , static_cast<Xn&&>(xn)...);
0156         }
0157     };
0158
0159     template <unsigned int n>
0160     struct foldl1_impl<n, when<(n >= 56)>> {
0161         template <
0162               typename F
0163             , typename X1,  typename X2,  typename X3,  typename X4,  typename X5,  typename X6,  typename X7
0164             , typename X8,  typename X9,  typename X10, typename X11, typename X12, typename X13, typename X14
0165             , typename X15, typename X16, typename X17, typename X18, typename X19, typename X20, typename X21
0166             , typename X22, typename X23, typename X24, typename X25, typename X26, typename X27, typename X28
0167             , typename X29, typename X30, typename X31, typename X32, typename X33, typename X34, typename X35
0168             , typename X36, typename X37, typename X38, typename X39, typename X40, typename X41, typename X42
0169             , typename X43, typename X44, typename X45, typename X46, typename X47, typename X48, typename X49
0170             , typename X50, typename X51, typename X52, typename X53, typename X54, typename X55, typename X56
0171             , typename ...Xn
0172         >
0173         static constexpr decltype(auto)
0174         apply(F&& f
0175               , X1&& x1,   X2&& x2,   X3&& x3,   X4&& x4,   X5&& x5,   X6&& x6,   X7&& x7
0176               , X8&& x8,   X9&& x9,   X10&& x10, X11&& x11, X12&& x12, X13&& x13, X14&& x14
0177               , X15&& x15, X16&& x16, X17&& x17, X18&& x18, X19&& x19, X20&& x20, X21&& x21
0178               , X22&& x22, X23&& x23, X24&& x24, X25&& x25, X26&& x26, X27&& x27, X28&& x28
0179               , X29&& x29, X30&& x30, X31&& x31, X32&& x32, X33&& x33, X34&& x34, X35&& x35
0180               , X36&& x36, X37&& x37, X38&& x38, X39&& x39, X40&& x40, X41&& x41, X42&& x42
0181               , X43&& x43, X44&& x44, X45&& x45, X46&& x46, X47&& x47, X48&& x48, X49&& x49
0182               , X50&& x50, X51&& x51, X52&& x52, X53&& x53, X54&& x54, X55&& x55, X56&& x56
0183               , Xn&& ...xn)
0184         {
0185             return foldl1_impl<sizeof...(xn) + 1>::apply(
0186                 f,
0187                 f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(
0188                     static_cast<X1&&>(x1),    static_cast<X2&&>(x2)),   static_cast<X3&&>(x3)),   static_cast<X4&&>(x4)),   static_cast<X5&&>(x5)),   static_cast<X6&&>(x6)),   static_cast<X7&&>(x7)),
0189                     static_cast<X8&&>(x8)),   static_cast<X9&&>(x9)),   static_cast<X10&&>(x10)), static_cast<X11&&>(x11)), static_cast<X12&&>(x12)), static_cast<X13&&>(x13)), static_cast<X14&&>(x14)),
0190                     static_cast<X15&&>(x15)), static_cast<X16&&>(x16)), static_cast<X17&&>(x17)), static_cast<X18&&>(x18)), static_cast<X19&&>(x19)), static_cast<X20&&>(x20)), static_cast<X21&&>(x21)),
0191                     static_cast<X22&&>(x22)), static_cast<X23&&>(x23)), static_cast<X24&&>(x24)), static_cast<X25&&>(x25)), static_cast<X26&&>(x26)), static_cast<X27&&>(x27)), static_cast<X28&&>(x28)),
0192                     static_cast<X29&&>(x29)), static_cast<X30&&>(x30)), static_cast<X31&&>(x31)), static_cast<X32&&>(x32)), static_cast<X33&&>(x33)), static_cast<X34&&>(x34)), static_cast<X35&&>(x35)),
0193                     static_cast<X36&&>(x36)), static_cast<X37&&>(x37)), static_cast<X38&&>(x38)), static_cast<X39&&>(x39)), static_cast<X40&&>(x40)), static_cast<X41&&>(x41)), static_cast<X42&&>(x42)),
0194                     static_cast<X43&&>(x43)), static_cast<X44&&>(x44)), static_cast<X45&&>(x45)), static_cast<X46&&>(x46)), static_cast<X47&&>(x47)), static_cast<X48&&>(x48)), static_cast<X49&&>(x49)),
0195                     static_cast<X50&&>(x50)), static_cast<X51&&>(x51)), static_cast<X52&&>(x52)), static_cast<X53&&>(x53)), static_cast<X54&&>(x54)), static_cast<X55&&>(x55)), static_cast<X56&&>(x56))
0196                 , static_cast<Xn&&>(xn)...);
0197         }
0198     };
0199     //! @endcond
0200
0201     struct foldl1_t {
0202         template <typename F, typename X1, typename ...Xn>
0203         constexpr decltype(auto) operator()(F&& f, X1&& x1, Xn&& ...xn) const {
0204             return foldl1_impl<sizeof...(xn) + 1>::apply(
0205                 static_cast<F&&>(f), static_cast<X1&&>(x1), static_cast<Xn&&>(xn)...
0206             );
0207         }
0208     };
0209
0210     BOOST_HANA_INLINE_VARIABLE constexpr foldl1_t foldl1{};
0211     BOOST_HANA_INLINE_VARIABLE constexpr auto foldl = foldl1;
0212 }} }} // end namespace boost::hana
0213
0214 #endif // !BOOST_HANA_DETAIL_VARIADIC_FOLDL1_HPP