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[libvmake] allow concat multiple sequences

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方而静 2023-07-20 00:11:54 +08:00
parent 4b183a10c2
commit a96009adf7
2 changed files with 42 additions and 16 deletions
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9
libvmake/examples/concating.cpp Normal file
View File

@ -0,0 +1,9 @@
#include "../vmake.hpp"
#include <vector>
using namespace std;
int main() {
vmake::outputln(cout, " ", vmake::concat(vmake::range(1, 3)
, vmake::range(1, 4), vmake::range(1, 4, 2)));
return 0;
}

49
libvmake/vmake.hpp
View File

@ -319,36 +319,51 @@ inline auto repeat_n(Tval &&x, size_t n) {
namespace details {
template<typename Gen1, typename Gen2>
template<typename T, size_t ...index>
inline bool concat_terminate_helper(T &g, std::index_sequence<index...> seq) {
bool res = true;
void(std::array<int, seq.size()>{
(!res || std::get<index>(g).is_terminated() || (res = false))...
});
return res;
}
template<typename Res, typename T, size_t ...index>
inline Res concat_call_helper(T &g, std::index_sequence<index...> seq) {
polyfill::optional<Res> x;
void(std::array<int, seq.size()>{
(x.has_value() || std::get<index>(g).is_terminated()
|| (x.emplace(std::move(std::get<index>(g)()))))...
});
if (!x.has_value()) throw sequence_terminated_error();
return *x;
}
template<typename Gen1, typename ...Gen>
struct concator {
using result = typename Gen1::result;
using core = Gen1;
using core2 = Gen2;
using core = std::tuple<Gen1, Gen...>;
Gen1 g1;
Gen2 g2;
core g;
concator(Gen1 &&g1, Gen2 &&g2) : g1(std::move(g1)), g2(std::move(g2)) {}
concator(concator<Gen1, Gen2> &&c) = default;
concator(const concator<Gen1, Gen2> &c) = default;
// concator<Gen1, Gen2>& operator=(concator<Gen1, Gen2> &&c) = default;
concator(Gen1&& g1, Gen&&... g2) : g(std::forward<Gen1>(g1), std::forward<Gen>(g2)...) {}
concator(concator<Gen1, Gen...>&&) = default;
concator(const concator<Gen1, Gen...>&) = default;
bool is_terminated() const noexcept {
return g1.is_terminated() && g2.is_terminated();
return concat_terminate_helper(g, std::make_index_sequence<sizeof...(Gen) + 1>());
}
auto operator()() {
if (g1.is_terminated()) return g2();
return g1();
return concat_call_helper<result>(g, std::make_index_sequence<sizeof...(Gen) + 1>());
}
};
} // namespace details
template<typename Gen1, typename Gen2>
inline constexpr auto concat(Gen1 &&x, Gen2 &&y) noexcept {
return details::concator<typename std::decay<Gen1>::type
, typename std::decay<Gen2>::type>(std::forward<Gen1>(x), std::forward<Gen2>(y));
template<typename ...Gen>
inline constexpr auto concat(Gen&&... g) noexcept {
return details::concator<typename std::decay<Gen>::type...>(std::forward<Gen>(g)...);
}
namespace details {
@ -685,6 +700,8 @@ using empty_sequence_int = decltype(nothing<int>());
static_assert(is_sequence_t<empty_sequence_int>::value, "");
static_assert(is_sequence_t<decltype(take(empty_sequence_int{}, 1))>::value, "");
static_assert(is_sequence_t<decltype(group<20>(empty_sequence_int{}))>::value, "");
static_assert(is_sequence_t<decltype(concat(empty_sequence_int{}
, empty_sequence_int{}))>::value, "");
static_assert(!is_sequence_t<int>::value, "");
static_assert(!is_sequence_t<std::less<int>>::value, "");