51 lines
1.0 KiB
C
51 lines
1.0 KiB
C
// { dg-options "-std=gnu++0x" }
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// { dg-do "run" }
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// A basic implementation of TR1's mem_fn using variadic teplates
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// Contributed by Douglas Gregor <doug.gregor@gmail.com>
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#include <cassert>
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template<typename R, typename Class, typename... Args>
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class Mem_fn
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{
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public:
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explicit Mem_fn(R (Class::*pmf)(Args...)) : pmf(pmf) { }
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R operator()(Class& object, Args... args)
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{
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return (object.*pmf)(args...);
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}
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R operator()(Class* object, Args... args)
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{
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return (object->*pmf)(args...);
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}
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R (Class::*pmf)(Args...);
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};
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template<typename R, typename Class, typename... Args>
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inline Mem_fn<R, Class, Args...>
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mem_fn(R (Class::* pmf)(Args...))
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{
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return Mem_fn<R, Class, Args...>(pmf);
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}
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class X {
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public:
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int negate(int x) { return -x; }
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int plus(int x, int y) { return x + y; }
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};
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int main()
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{
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X x;
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X* xp = &x;
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assert(mem_fn(&X::negate)(x, 17) == -17);
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assert(mem_fn(&X::negate)(xp, 17) == -17);
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assert(mem_fn(&X::plus)(x, 17, 25) == 42);
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assert(mem_fn(&X::plus)(xp, 17, 25) == 42);
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return 0;
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}
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