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iterator/zip: use the iterable concept for zip construction

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This commit is contained in:
Danny Robson 2020-02-24 14:39:58 +11:00
parent 3791c8b8ee
commit ebd88b25e7
1 changed files with 18 additions and 0 deletions
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18
iterator/zip.hpp
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@ -9,6 +9,7 @@
#pragma once #pragma once
#include "iota.hpp" #include "iota.hpp"
#include "../concepts.hpp"
#include "../tuple/value.hpp" #include "../tuple/value.hpp"
#include "../variadic.hpp" #include "../variadic.hpp"
#include "../functor.hpp" #include "../functor.hpp"
@ -81,6 +82,21 @@ namespace cruft::iterator {
} }
decltype (auto)
operator* (void) const
{
// We deliberately construct a tuple manually here to reduce
// the risk of dangling references. `forward_as_tuple` and
// `make_tuple` have resulted in references to locals in the
// past.
return std::tuple<
decltype(*std::get<Indices> (m_iterators))...
> (
*std::get<Indices> (m_iterators)...
);
}
bool bool
operator== (const zipped_iterator &rhs) const operator== (const zipped_iterator &rhs) const
{ {
@ -178,6 +194,7 @@ namespace cruft::iterator {
/// ///
/// eg, cruft::zip ({1,2,3}, {4,5,6}) ~= {{1,4},{2,5},{3,6}} /// eg, cruft::zip ({1,2,3}, {4,5,6}) ~= {{1,4},{2,5},{3,6}}
template <typename ...ContainerT> template <typename ...ContainerT>
requires (cruft::concepts::iterable<ContainerT> && ...)
decltype(auto) decltype(auto)
zip (ContainerT&&... data) zip (ContainerT&&... data)
{ {
@ -199,6 +216,7 @@ namespace cruft::iterator {
/// ///
/// eg, cruft::izip ("abc") ~= {{0,'a'},{1,'b'},{2,'c'}} /// eg, cruft::izip ("abc") ~= {{0,'a'},{1,'b'},{2,'c'}}
template <typename ...ContainerT> template <typename ...ContainerT>
requires (cruft::concepts::iterable<ContainerT> && ...)
decltype(auto) decltype(auto)
izip (ContainerT&&... data) izip (ContainerT&&... data)
{ {