88 lines
2.0 KiB
C++
88 lines
2.0 KiB
C++
// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s
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// expected-no-diagnostics
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// Example function implementation from the variadic templates proposal,
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// ISO C++ committee document number N2080.
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template<typename Signature> class function;
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template<typename R, typename... Args> class invoker_base {
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public:
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virtual ~invoker_base() { }
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virtual R invoke(Args...) = 0;
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virtual invoker_base* clone() = 0;
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};
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template<typename F, typename R, typename... Args>
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class functor_invoker : public invoker_base<R, Args...> {
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public:
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explicit functor_invoker(const F& f) : f(f) { }
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R invoke(Args... args) { return f(args...); }
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functor_invoker* clone() { return new functor_invoker(f); }
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private:
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F f;
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};
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template<typename R, typename... Args>
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class function<R (Args...)> {
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public:
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typedef R result_type;
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function() : invoker (0) { }
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function(const function& other) : invoker(0) {
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if (other.invoker)
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invoker = other.invoker->clone();
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}
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template<typename F> function(const F& f) : invoker(0) {
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invoker = new functor_invoker<F, R, Args...>(f);
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}
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~function() {
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if (invoker)
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delete invoker;
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}
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function& operator=(const function& other) {
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function(other).swap(*this);
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return *this;
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}
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template<typename F>
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function& operator=(const F& f) {
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function(f).swap(*this);
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return *this;
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}
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void swap(function& other) {
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invoker_base<R, Args...>* tmp = invoker;
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invoker = other.invoker;
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other.invoker = tmp;
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}
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result_type operator()(Args... args) const {
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return invoker->invoke(args...);
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}
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private:
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invoker_base<R, Args...>* invoker;
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};
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template<typename T>
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struct add {
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T operator()(T x, T y) { return x + y; }
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};
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int add_ints(int x, int y) { return x + y; }
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void test_function() {
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function<int(int, int)> f2a;
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function<int(int, int)> f2b = add<int>();
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function<int(int, int)> f2c = add<float>();
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function<int(int, int)> f2d(f2b);
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function<int(int, int)> f2e = &add_ints;
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f2c = f2d;
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f2d = &add_ints;
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f2c(1.0, 3);
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}
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