Add generic macro for defining (custom) type checks
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@ -48,45 +48,38 @@ struct IsCString
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template <typename T> struct IsString : Bool<IsCString<T>::value || IsSpecializationOf<T, std::basic_string>::value> {
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};
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/// \cond
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namespace Detail {
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// allow ADL with custom begin/end
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using std::begin;
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using std::end;
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template <typename T>
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auto isIteratableImpl(int) -> decltype(
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/*!
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* \def CPP_UTILITIES_PP_COMMA
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* \brief The CPP_UTILITIES_PP_COMMA macro helps passing "," as a macro argument.
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*/
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#define CPP_UTILITIES_PP_COMMA ,
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/*!
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* \def CPP_UTILITIES_TRAITS_DEFINE_TYPE_CHECK
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* \brief The CPP_UTILITIES_TRAITS_DEFINE_TYPE_CHECK macro defines a type trait for checking whether some operation can be done with
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* a particular type.
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* \sa Traits::HasSize or Traits::IsIteratable for an example how to use it.
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*/
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#define CPP_UTILITIES_TRAITS_DEFINE_TYPE_CHECK(CheckName, CheckCode) \
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namespace Detail { \
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template <typename T> auto CheckName(int) -> decltype(CheckCode, Bool<true>{}); \
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template <typename T> Bool<false> CheckName(...); \
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} \
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template <typename T> using CheckName = decltype(Detail::CheckName<T>(0))
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CPP_UTILITIES_TRAITS_DEFINE_TYPE_CHECK(HasSize, std::is_integral<decltype(std::declval<T &>().size())>::value);
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CPP_UTILITIES_TRAITS_DEFINE_TYPE_CHECK(IsReservable, std::declval<T &>().reserve(0u));
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CPP_UTILITIES_TRAITS_DEFINE_TYPE_CHECK(IsIteratable,
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// begin/end and operator !=
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begin(std::declval<T &>()) != end(std::declval<T &>()),
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std::begin(std::declval<T &>())
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!= std::end(std::declval<T &>()) CPP_UTILITIES_PP_COMMA
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// operator ,
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void(),
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void() CPP_UTILITIES_PP_COMMA
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// operator ++
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++std::declval<decltype(begin(std::declval<T &>())) &>(),
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++ std::declval<decltype(begin(std::declval<T &>())) &>() CPP_UTILITIES_PP_COMMA
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// operator*
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void(*begin(std::declval<T &>())), Bool<true>{});
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void(*begin(std::declval<T &>())));
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template <typename T> Bool<false> isIteratableImpl(...);
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} // namespace Detail
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/// \endcond
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template <typename T> using IsIteratable = decltype(Detail::isIteratableImpl<T>(0));
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/// \cond
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namespace Detail {
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template <typename T> auto hasSizeImpl(int) -> decltype(std::declval<T &>().size(), Bool<true>{});
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template <typename T> Bool<false> hasSizeImpl(...);
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} // namespace Detail
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/// \endcond
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template <typename T> using HasSize = decltype(Detail::hasSizeImpl<T>(0));
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/// \cond
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namespace Detail {
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template <typename T> auto isReservable(int) -> decltype(std::declval<T &>().reserve(0u), Bool<true>{});
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template <typename T> Bool<false> isReservable(...);
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} // namespace Detail
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/// \endcond
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template <typename T> using IsReservable = decltype(Detail::isReservable<T>(0));
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} // namespace Traits
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#endif // CPP_UTILITIES_TRAITS_H
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