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//template<typename T> | |
//bool Foo(T a, T b) { | |
// T c = a + b; | |
// return a == c; | |
//} | |
// | |
//Expands to: | |
//------------- begin ------------- | |
#include <iostream> | |
class FooInterface { | |
public: | |
virtual ~FooInterface() {} | |
// Caller ensures that `this` and rhs have the same dynamic type. | |
virtual FooInterface* Add(FooInterface* rhs) = 0; | |
virtual bool Equal(FooInterface* rhs) = 0; | |
}; | |
template<typename T> | |
struct FooInterfaceImpl : FooInterface { | |
FooInterfaceImpl(const T& v) : value(v) {} | |
FooInterface* Add(FooInterface* rhs_i) override { | |
auto rhs = static_cast<FooInterfaceImpl<T>*>(rhs_i); | |
std::cout << rhs->value << "\n"; | |
return new FooInterfaceImpl(value + rhs->value); | |
} | |
bool Equal(FooInterface* rhs_i) override { | |
auto rhs = static_cast<FooInterfaceImpl<T>*>(rhs_i); | |
return value == rhs->value; | |
} | |
T padding[10000]; | |
T value; | |
}; | |
struct FII2 : FooInterface { | |
FooInterface* Add(FooInterface *rhs) override { | |
return 0; | |
} | |
bool Equal(FooInterface *rhs) override { | |
return false; | |
} | |
}; | |
bool Foo(FooInterface* a, FooInterface* b) { | |
FooInterface* c = a->Add(b); | |
return a->Equal(c); | |
} | |
//------------- end ------------- | |
#include <cassert> | |
int main() { | |
{ | |
FooInterfaceImpl<int> a(3), b(4); | |
assert(!Foo(&a, &b)); | |
} | |
{ | |
FooInterfaceImpl<int> a(3), b(0); | |
assert(Foo(&a, &b)); | |
} | |
FII2 a; | |
FooInterfaceImpl<int> b(0); | |
std::cout << "Foo(b, a) = " << Foo(&b, &a) << "\n"; | |
} |
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