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Move constexpr_first/last to common.h

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This keeps it with constexpr_sum and the other metafunctions.
This commit is contained in:
Jason Rhinelander 2017-01-22 19:12:24 -05:00 committed by Wenzel Jakob
parent 3b4b921192
commit 34d308adf0
2 changed files with 20 additions and 19 deletions
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19
include/pybind11/cast.h
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@ -1314,25 +1314,6 @@ private:
std::tuple<make_caster<Args>...> value;
};
NAMESPACE_BEGIN(constexpr_impl)
/// Implementation details for constexpr functions
constexpr int first(int i) { return i; }
template <typename T, typename... Ts>
constexpr int first(int i, T v, Ts... vs) { return v ? i : first(i + 1, vs...); }
constexpr int last(int /*i*/, int result) { return result; }
template <typename T, typename... Ts>
constexpr int last(int i, int result, T v, Ts... vs) { return last(i + 1, v ? i : result, vs...); }
NAMESPACE_END(constexpr_impl)
/// Return the index of the first type in Ts which satisfies Predicate<T>
template <template<typename> class Predicate, typename... Ts>
constexpr int constexpr_first() { return constexpr_impl::first(0, Predicate<Ts>::value...); }
/// Return the index of the last type in Ts which satisfies Predicate<T>
template <template<typename> class Predicate, typename... Ts>
constexpr int constexpr_last() { return constexpr_impl::last(0, -1, Predicate<Ts>::value...); }
/// Helper class which collects only positional arguments for a Python function call.
/// A fancier version below can collect any argument, but this one is optimal for simple calls.
template <return_value_policy policy>

20
include/pybind11/common.h
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@ -449,6 +449,26 @@ constexpr size_t constexpr_sum() { return 0; }
template <typename T, typename... Ts>
constexpr size_t constexpr_sum(T n, Ts... ns) { return size_t{n} + constexpr_sum(ns...); }
NAMESPACE_BEGIN(constexpr_impl)
/// Implementation details for constexpr functions
constexpr int first(int i) { return i; }
template <typename T, typename... Ts>
constexpr int first(int i, T v, Ts... vs) { return v ? i : first(i + 1, vs...); }
constexpr int last(int /*i*/, int result) { return result; }
template <typename T, typename... Ts>
constexpr int last(int i, int result, T v, Ts... vs) { return last(i + 1, v ? i : result, vs...); }
NAMESPACE_END(constexpr_impl)
/// Return the index of the first type in Ts which satisfies Predicate<T>. Returns sizeof...(Ts) if
/// none match.
template <template<typename> class Predicate, typename... Ts>
constexpr int constexpr_first() { return constexpr_impl::first(0, Predicate<Ts>::value...); }
/// Return the index of the last type in Ts which satisfies Predicate<T>, or -1 if none match.
template <template<typename> class Predicate, typename... Ts>
constexpr int constexpr_last() { return constexpr_impl::last(0, -1, Predicate<Ts>::value...); }
// Extracts the first type from the template parameter pack matching the predicate, or Default if none match.
template <template<class> class Predicate, class Default, class... Ts> struct first_of;
template <template<class> class Predicate, class Default> struct first_of<Predicate, Default> {