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Diffstat (limited to 'clang/test/CXX/temp/temp.decls/temp.variadic/example-bind.cpp')
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1 files changed, 352 insertions, 0 deletions
diff --git a/clang/test/CXX/temp/temp.decls/temp.variadic/example-bind.cpp b/clang/test/CXX/temp/temp.decls/temp.variadic/example-bind.cpp new file mode 100644 index 0000000..db28eea --- /dev/null +++ b/clang/test/CXX/temp/temp.decls/temp.variadic/example-bind.cpp @@ -0,0 +1,352 @@ +// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s + +// Example bind implementation from the variadic templates proposal, +// ISO C++ committee document number N2080. + +// Helper type traits +template<typename T> +struct add_reference { + typedef T &type; +}; + +template<typename T> +struct add_reference<T&> { + typedef T &type; +}; + +template<typename T> +struct add_const_reference { + typedef T const &type; +}; + +template<typename T> +struct add_const_reference<T&> { + typedef T &type; +}; + +template<typename T, typename U> +struct is_same { + static const bool value = false; +}; + +template<typename T> +struct is_same<T, T> { + static const bool value = true; +}; + +template<typename T> +class reference_wrapper { + T *ptr; + +public: + reference_wrapper(T& t) : ptr(&t) { } + operator T&() const { return *ptr; } +}; + +template<typename T> reference_wrapper<T> ref(T& t) { + return reference_wrapper<T>(t); +} +template<typename T> reference_wrapper<const T> cref(const T& t) { + return reference_wrapper<const T>(t); +} + +template<typename... Values> class tuple; + +// Basis case: zero-length tuple +template<> class tuple<> { }; + +template<typename Head, typename... Tail> +class tuple<Head, Tail...> : private tuple<Tail...> { + typedef tuple<Tail...> inherited; + +public: + tuple() { } + // implicit copy-constructor is okay + + // Construct tuple from separate arguments. + tuple(typename add_const_reference<Head>::type v, + typename add_const_reference<Tail>::type... vtail) + : m_head(v), inherited(vtail...) { } + + // Construct tuple from another tuple. + template<typename... VValues> tuple(const tuple<VValues...>& other) + : m_head(other.head()), inherited(other.tail()) { } + + template<typename... VValues> tuple& + operator=(const tuple<VValues...>& other) { + m_head = other.head(); + tail() = other.tail(); + return *this; + } + + typename add_reference<Head>::type head() { return m_head; } + typename add_reference<const Head>::type head() const { return m_head; } + inherited& tail() { return *this; } + const inherited& tail() const { return *this; } + +protected: + Head m_head; +}; + +// Creation functions +template<typename T> +struct make_tuple_result { + typedef T type; +}; + +template<typename T> +struct make_tuple_result<reference_wrapper<T> > { + typedef T& type; +}; + +template<typename... Values> +tuple<typename make_tuple_result<Values>::type...> +make_tuple(const Values&... values) { + return tuple<typename make_tuple_result<Values>::type...>(values...); +} + +template<typename... Values> +tuple<Values&...> tie(Values&... values) { + return tuple<Values&...>(values...); +} + +// Helper classes +template<typename Tuple> struct tuple_size; + +template<typename... Values> struct tuple_size<tuple<Values...> > { + static const int value = sizeof...(Values); +}; + +template<int I, typename Tuple> struct tuple_element; + +template<int I, typename Head, typename... Tail> +struct tuple_element<I, tuple<Head, Tail...> > { + typedef typename tuple_element<I-1, tuple<Tail...> >::type type; +}; + +template<typename Head, typename... Tail> +struct tuple_element<0, tuple<Head, Tail...> > { + typedef Head type; +}; + +// Element access +template<int I, typename Tuple> class get_impl; +template<int I, typename Head, typename... Values> +class get_impl<I, tuple<Head, Values...> > { + typedef typename tuple_element<I-1, tuple<Values...> >::type Element; + typedef typename add_reference<Element>::type RJ; + typedef typename add_const_reference<Element>::type PJ; + typedef get_impl<I-1, tuple<Values...> > Next; +public: + static RJ get(tuple<Head, Values...>& t) { return Next::get(t.tail()); } + static PJ get(const tuple<Head, Values...>& t) { return Next::get(t.tail()); } +}; + +template<typename Head, typename... Values> +class get_impl<0, tuple<Head, Values...> > { + typedef typename add_reference<Head>::type RJ; + typedef typename add_const_reference<Head>::type PJ; +public: + static RJ get(tuple<Head, Values...>& t) { return t.head(); } + static PJ get(const tuple<Head, Values...>& t) { return t.head(); } +}; + +template<int I, typename... Values> typename add_reference< +typename tuple_element<I, tuple<Values...> >::type >::type +get(tuple<Values...>& t) { + return get_impl<I, tuple<Values...> >::get(t); +} + +template<int I, typename... Values> typename add_const_reference< +typename tuple_element<I, tuple<Values...> >::type >::type +get(const tuple<Values...>& t) { + return get_impl<I, tuple<Values...> >::get(t); +} + +// Relational operators +inline bool operator==(const tuple<>&, const tuple<>&) { return true; } + +template<typename T, typename... TTail, typename U, typename... UTail> +bool operator==(const tuple<T, TTail...>& t, const tuple<U, UTail...>& u) { + return t.head() == u.head() && t.tail() == u.tail(); +} + +template<typename... TValues, typename... UValues> +bool operator!=(const tuple<TValues...>& t, const tuple<UValues...>& u) { + return !(t == u); +} + +inline bool operator<(const tuple<>&, const tuple<>&) { return false; } + +template<typename T, typename... TTail, typename U, typename... UTail> +bool operator<(const tuple<T, TTail...>& t, const tuple<U, UTail...>& u) { + return (t.head() < u.head() || (!(t.head() < u.head()) && t.tail() < u.tail())); +} + +template<typename... TValues, typename... UValues> +bool operator>(const tuple<TValues...>& t, const tuple<UValues...>& u) { + return u < t; +} + +template<typename... TValues, typename... UValues> +bool operator<=(const tuple<TValues...>& t, const tuple<UValues...>& u) { + return !(u < t); +} + +template<typename... TValues, typename... UValues> +bool operator>=(const tuple<TValues...>& t, const tuple<UValues...>& u) { + return !(t < u); +} + +// make_indices helper +template<int...> struct int_tuple {}; +// make_indexes impl is a helper for make_indexes +template<int I, typename IntTuple, typename... Types> struct make_indexes_impl; + +template<int I, int... Indexes, typename T, typename... Types> +struct make_indexes_impl<I, int_tuple<Indexes...>, T, Types...> { + typedef typename make_indexes_impl<I+1, int_tuple<Indexes..., I>, Types...>::type type; +}; + +template<int I, int... Indexes> +struct make_indexes_impl<I, int_tuple<Indexes...> > { + typedef int_tuple<Indexes...> type; +}; + +template<typename... Types> +struct make_indexes : make_indexes_impl<0, int_tuple<>, Types...> { +}; + +// Bind +template<typename T> struct is_bind_expression { + static const bool value = false; +}; + +template<typename T> struct is_placeholder { + static const int value = 0; +}; + + +template<typename F, typename... BoundArgs> class bound_functor { + typedef typename make_indexes<BoundArgs...>::type indexes; +public: + typedef typename F::result_type result_type; + explicit bound_functor(const F& f, const BoundArgs&... bound_args) + : f(f), bound_args(bound_args...) { } template<typename... Args> + typename F::result_type operator()(Args&... args); +private: F f; + tuple<BoundArgs...> bound_args; +}; + +template<typename F, typename... BoundArgs> +inline bound_functor<F, BoundArgs...> bind(const F& f, const BoundArgs&... bound_args) { + return bound_functor<F, BoundArgs...>(f, bound_args...); +} + +template<typename F, typename ...BoundArgs> +struct is_bind_expression<bound_functor<F, BoundArgs...> > { + static const bool value = true; +}; + +// enable_if helper +template<bool Cond, typename T = void> +struct enable_if; + +template<typename T> +struct enable_if<true, T> { + typedef T type; +}; + +template<typename T> +struct enable_if<false, T> { }; + +// safe_tuple_element helper +template<int I, typename Tuple, typename = void> +struct safe_tuple_element { }; + +template<int I, typename... Values> +struct safe_tuple_element<I, tuple<Values...>, + typename enable_if<(I >= 0 && I < tuple_size<tuple<Values...> >::value)>::type> { + typedef typename tuple_element<I, tuple<Values...> >::type type; +}; + +// mu +template<typename Bound, typename... Args> +inline typename safe_tuple_element<is_placeholder<Bound>::value -1, + tuple<Args...> >::type +mu(Bound& bound_arg, const tuple<Args&...>& args) { + return get<is_placeholder<Bound>::value-1>(args); +} + +template<typename T, typename... Args> +inline T& mu(reference_wrapper<T>& bound_arg, const tuple<Args&...>&) { + return bound_arg.get(); +} + +template<typename F, int... Indexes, typename... Args> +inline typename F::result_type +unwrap_and_forward(F& f, int_tuple<Indexes...>, const tuple<Args&...>& args) { + return f(get<Indexes>(args)...); +} + +template<typename Bound, typename... Args> +inline typename enable_if<is_bind_expression<Bound>::value, + typename Bound::result_type>::type +mu(Bound& bound_arg, const tuple<Args&...>& args) { + typedef typename make_indexes<Args...>::type Indexes; + return unwrap_and_forward(bound_arg, Indexes(), args); +} + +template<typename T> +struct is_reference_wrapper { + static const bool value = false; +}; + +template<typename T> +struct is_reference_wrapper<reference_wrapper<T>> { + static const bool value = true; +}; + +template<typename Bound, typename... Args> +inline typename enable_if<(!is_bind_expression<Bound>::value + && !is_placeholder<Bound>::value + && !is_reference_wrapper<Bound>::value), + Bound&>::type +mu(Bound& bound_arg, const tuple<Args&...>&) { + return bound_arg; +} + +template<typename F, typename... BoundArgs, int... Indexes, typename... Args> +typename F::result_type apply_functor(F& f, tuple<BoundArgs...>& bound_args, + int_tuple<Indexes...>, + const tuple<Args&...>& args) { + return f(mu(get<Indexes>(bound_args), args)...); +} + +template<typename F, typename... BoundArgs> +template<typename... Args> +typename F::result_type bound_functor<F, BoundArgs...>::operator()(Args&... args) { + return apply_functor(f, bound_args, indexes(), tie(args...)); +} + +template<int N> struct placeholder { }; +template<int N> +struct is_placeholder<placeholder<N>> { + static const int value = N; +}; + +template<typename T> +struct plus { + typedef T result_type; + + T operator()(T x, T y) { return x + y; } +}; + +placeholder<1> _1; + +// Test bind +void test_bind() { + int x = 17; + int y = 25; + bind(plus<int>(), x, _1)(y); +} |