first_function.h

// Description: First element function
// Documentation: functions.txt

#ifndef PASTELSYS_FIRST_FUNCTION_H
#define PASTELSYS_FIRST_FUNCTION_H

#include "pastel/sys/function/function_concept.h"

namespace Pastel
{

    //! A function f(x) = x.first.
    struct First_Function
    {
        template <typename Type>
        decltype(auto) operator()(Type&& x) const
        {
            // The parenthesis here are important,
            // to create a reference.
            return (x.first);
        }
    };

}

#endif