我正在尝试从较小的范围中创建笛卡尔积范围。我想ranges::v3::view::cartesian_product
会起作用,但不知何故它不起作用。
如果我尝试直接使用容器创建笛卡尔积,我没有问题。编译如下:
#include <vector>
#include <range/v3/view/cartesian_product.hpp>
int main() {
std::vector<int> data1{1,5,2,7,6,3,4,8,9,0};
std::vector<int> data2{1,5,2,7,6,3,4,8,9,0};
auto range = ranges::v3::view::cartesian_product(data1, data2);
}
然而,一旦我开始使用过滤器:
#include <vector>
#include <range/v3/view/cartesian_product.hpp>
#include <range/v3/view/filter.hpp>
int main() {
std::vector<int> data1{1,5,2,7,6,3,4,8,9,0};
std::vector<int> data2{1,5,2,7,6,3,4,8,9,0};
auto range = ranges::v3::view::cartesian_product(
data1 | ranges::v3::view::filter([](int v) { return v%2; }),
data2);
}
我收到大量难以破译的编译错误,首先是:
In file included from contrib/range/v3/view/cartesian_product.hpp:21:0,
from cartesian-err.cpp:2:
contrib/range/v3/range_concepts.hpp: In instantiation of ‘class ranges::v3::cartesian_product_view<ranges::v3::remove_if_view<ranges::v3::iterator_range<__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >, __gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > > >, ranges::v3::logical_negate_<main()::<lambda(int)> > >, ranges::v3::iterator_range<__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >, __gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > > > >’:
cartesian-err.cpp:10:18: required from here
contrib/range/v3/range_concepts.hpp:78:50: error: no match for call to ‘(const ranges::v3::_begin_::fn) (const ranges::v3::remove_if_view<ranges::v3::iterator_range<__gnu_cxx::__normal_iterator<int*, std::vector<int> >, __gnu_cxx::__normal_iterator<int*, std::vector<int> > >, ranges::v3::logical_negate_<main()::<lambda(int)> > >&)’
using iterator_t = decltype(begin(std::declval<T &>()));
~~~~~^~~~~~~~~~~~~~~~~~~~~
我该如何解决它?
附:有没有一些关于 range-v3 库的好的文档?我找不到任何东西,我感觉我在黑暗中行走......