CODEWITHSUNDEEP
c++c++11variadic-templates
drb
drb

Reputation: 35

Type expression for a tuple representing arguments to a function

I'm looking for a way to create a type expression for a std::tuple representing the arguments required by a function. Consider the following:

template<typename F, typename ...args>
void myfunction(F&& function, A... args)
{
    std::tuple</*???*/> arguments;
    populate_tuple(arguments,args...);
    return apply(function,arguments);
}

... where F is a normal function type, apply() is a function that applies the arguments to the function, and populate_tuple() does some work on the arguments (including type conversions) before populating the tuple with the final arguments for the call to the function.

Note: I can't use args... in the declaration of the tuple, because these are not the types that the function is expecting - populate_tuple() does the conversion.

It feels to me as though the compiler has everything it needs to do this, but I don't know if the language supports it. Any ideas? All help appreciated.

Upvotes: 0

Views: 50

Answers (2)

Guillaume Racicot
Guillaume Racicot

Reputation: 41770

Does this work?

template<typename F, typename ...Args>
void myfunction(F&& function, Args&&... args) {
     return apply(std::forward<F>(function), std::make_tuple(std::forward<Args>(args)...));
}

Upvotes: 0

Igor Tandetnik
Igor Tandetnik

Reputation: 52471

Something along these lines, perhaps:

template <typename T> struct TupleOfArguments;

template <typename R, typename ... Args>
struct TupleOfArguments<R(Args...)> {
  typedef std::tuple<Args...> type;
};

Demo

Upvotes: 1

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