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// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s
// Example function implementation from the variadic templates proposal,
// ISO C++ committee document number N2080.
template<typename Signature> class function;
template<typename R, typename... Args> class invoker_base {
public:
virtual ~invoker_base() { }
virtual R invoke(Args...) = 0;
virtual invoker_base* clone() = 0;
};
template<typename F, typename R, typename... Args>
class functor_invoker : public invoker_base<R, Args...> {
public:
explicit functor_invoker(const F& f) : f(f) { }
R invoke(Args... args) { return f(args...); }
functor_invoker* clone() { return new functor_invoker(f); }
private:
F f;
};
template<typename R, typename... Args>
class function<R (Args...)> {
public:
typedef R result_type;
function() : invoker (0) { }
function(const function& other) : invoker(0) {
if (other.invoker)
invoker = other.invoker->clone();
}
template<typename F> function(const F& f) : invoker(0) {
invoker = new functor_invoker<F, R, Args...>(f);
}
~function() {
if (invoker)
delete invoker;
}
function& operator=(const function& other) {
function(other).swap(*this);
return *this;
}
template<typename F>
function& operator=(const F& f) {
function(f).swap(*this);
return *this;
}
void swap(function& other) {
invoker_base<R, Args...>* tmp = invoker;
invoker = other.invoker;
other.invoker = tmp;
}
result_type operator()(Args... args) const {
return invoker->invoke(args...);
}
private:
invoker_base<R, Args...>* invoker;
};
template<typename T>
struct add {
T operator()(T x, T y) { return x + y; }
};
int add_ints(int x, int y) { return x + y; }
void test_function() {
function<int(int, int)> f2a;
function<int(int, int)> f2b = add<int>();
function<int(int, int)> f2c = add<float>();
function<int(int, int)> f2d(f2b);
function<int(int, int)> f2e = &add_ints;
f2c = f2d;
f2d = &add_ints;
f2c(1.0, 3);
}
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