point_point_id.h

// Description: Point-id of a point
// DocumentationOf: point_concept.h

#ifndef PASTELSYS_POINT_POINT_ID_H
#define PASTELSYS_POINT_POINT_ID_H

#include "pastel/sys/point/point_concept.h"
#include "pastel/sys/function/identity_function.h"
#include "pastel/sys/type_traits/remove_cvref.h"
#include "pastel/sys/type_traits/compiles.h"

namespace Pastel
{

    template <
        typename Type,
        typename = decltype(pointPointId(std::declval<Type>()))>
    struct Point_HasPointId_Test {};

    template <typename Type>
    using Point_HasPointId =
        Compiles<Point_HasPointId_Test, Type>;

    template <
        typename Point,
        Requires<
            Not<Point_HasPointId<Point>>
        > = 0
    >
    decltype(auto) pointPointId(Point&& point)
    {
        return std::forward<Point>(point);
    }

}

namespace Pastel
{

    template <typename Point>
    using Point_PointId = 
        RemoveCvRef<decltype(pointPointId(std::declval<Point>()))>;

    template <typename Point>
    using Point_PointId_F = 
        Identity_F<Point_PointId<Point>>;

}

#endif