In the following code it seems that the variadic template version of Container doesn't inherit the name function of the single template version of Container, g++ 4.5.2 complains:
no matching function for call to ”Container<Variable1, Variable2>::name(Variable2)”
candidate is: std::string Container<First_Variable, Rest ...>::name(First_Variable) [with First_Variable = Variable1, Rest = {Variable2}, std::string = std::basic_string<char>]
The code:
#include "iostream"
#include "string"
using namespace std;
struct Variable1 {
string operator()() {
return string("var1");
}
};
struct Variable2 {
string operator()() {
return string("var2");
}
};
template<class... T> class Container;
template<class First_Variable, class... Rest>
class Container<First_Variable, Rest...> : public Container<Rest...> {
public:
string name(First_Variable variable) {
return variable();
}
};
template<class Variable> class Container<Variable> {
public:
string name(Variable variable) {
return variable();
}
};
int main(void) {
Container<Variable1, Variable2> c;
cout << "Variables in container: " << c.name(Variable1()) << ", " << c.name(Variable2()) << endl;
return 0;
}
What am I doing wrong or is this even supposed to work?
The name
are hiding the name of the base class. Try
template<class... T> class Container;
template<class First_Variable, class... Rest>
class Container<First_Variable, Rest...> : public Container<Rest...> {
public:
using Container<Rest...>::name;
string name(First_Variable variable) {
return variable();
}
};
template<class Variable> class Container<Variable> {
public:
string name(Variable variable) {
return variable();
}
};
If you are pedantic, then your partial specializations are incorrect. The C++11 spec terms ambiguous two partial specializations of the form <FixedParameter, Pack...>
and <FixedParameter>
. This was discussed and many people find it surprising, so some compilers do not implement that part of C++11.
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