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zymelaii.cpp
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zymelaii.cpp
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#include <type_traits>
#include <algorithm>
namespace detail {
template <typename T>
struct element_type {
template <typename G>
static constexpr auto check(int) -> typename G::value_type;
template <typename G>
static constexpr void check(...);
using type = decltype(check<T>(0));
};
template <typename T>
struct value_type_substituter;
template <template <typename...> typename T, typename E, typename... Args>
struct value_type_substituter<T<E, Args...>> {
//! FIXME: unsafe value_type substitution policy
template <typename V>
using type = T<V>;
};
} // namespace detail
template <typename T>
using element_type_t = typename detail::element_type<T>::type;
template <typename T, typename E>
using new_container_type_t =
typename detail::value_type_substituter<T>::template type<E>;
namespace solution {
template <
typename T,
typename Fn,
typename E = element_type_t<T>,
typename = std::enable_if_t<
!std::is_same_v<E, void> && std::is_invocable_v<Fn, E>>>
auto operator|(const T& seq, Fn transform) {
using value_type = std::invoke_result_t<Fn, E>;
if constexpr (std::is_same_v<value_type, void>) {
for (auto& e : seq) { transform(e); }
} else {
new_container_type_t<T, value_type> resp;
std::transform(
seq.begin(), seq.end(), std::back_inserter(resp), transform);
return std::move(resp);
}
}
} // namespace solution
#include <vector>
#include <iostream>
int main(int argc, char* argv[]) {
using namespace solution;
std::vector<int> v{1, 2, 3};
v | [](auto i) {
return i * i;
} | [](auto i) {
std::cout << i << " ";
};
return 0;
}