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Replace std::mem_fn with custom lambda in ranges

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This commit is contained in:
Maxime Coste 2019-01-24 21:09:07 +11:00
parent 3e89148d74
commit b91367f8a3
1 changed files with 23 additions and 3 deletions
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26
src/ranges.hh
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@ -5,7 +5,6 @@
#include <utility> #include <utility>
#include <iterator> #include <iterator>
#include <numeric> #include <numeric>
#include <functional>
#include "constexpr_utils.hh" #include "constexpr_utils.hh"
@ -191,10 +190,31 @@ inline auto transform(Transform t)
}); });
} }
template<typename T, typename U, typename = void>
struct is_pointer_like : std::false_type {};
template<typename T, typename U>
struct is_pointer_like<T, U, std::enable_if_t<std::is_same_v<std::decay_t<decltype(*std::declval<U>())>, std::decay_t<T>>>> : std::true_type {};
template<typename M, typename T> template<typename M, typename T>
inline auto transform(M T::*m) inline auto transform(M T::*member)
{ {
return transform(std::mem_fn(std::forward<decltype(m)>(m))); return transform([member](auto&& arg) -> decltype(auto) {
using Arg = decltype(arg);
using Member = decltype(member);
auto get_object = [&] () mutable -> decltype(auto) {
if constexpr (is_pointer_like<T, Arg>::value)
return *std::forward<Arg>(arg);
else
return std::forward<Arg>(arg);
};
if constexpr (std::is_member_function_pointer_v<Member>)
return (get_object().*member)();
else
return get_object().*member;
});
} }
template<typename Range, bool escape, bool include_separator, template<typename Range, bool escape, bool include_separator,