point_axis.h

// Description: Coordinate of a point
// DocumentationOf: point_concept.h

#ifndef PASTELSYS_POINT_AXIS_H
#define PASTELSYS_POINT_AXIS_H

#include "pastel/sys/point/point_concept.h"
#include "pastel/sys/type_traits/compiles.h"
#include "pastel/sys/real/real_ring_concept.h"

namespace Pastel
{

    // Coordinates by point.pointAxis(i)

    template <
        typename Point,
        typename = decltype(std::declval<Point>().pointAxis((integer)0))>
    struct Point_HasMemberPointAxis_Test
    {};

    template <typename Type>
    using Point_HasMemberPointAxis = 
        Compiles<Point_HasMemberPointAxis_Test, Type>;

    template <
        typename Point,
        Requires<
            Point_HasMemberPointAxis<Point>
        > = 0
    >
    decltype(auto) pointAxis(Point&& point, integer axis)
    {
        return std::forward<Point>(point).pointAxis(axis);
    }

}

namespace Pastel
{

    // Coordinates by point[i]

    template <
        typename Point,
        typename = decltype(std::declval<Point>()[(integer)0])>
    struct Point_HasIndexing_Test {};

    template <typename Type>
    using Point_HasIndexing = 
        Compiles<Point_HasIndexing_Test, Type>;

    template <
        typename Point,
        Requires<
            Point_HasIndexing<Point>,
            Not<Point_HasMemberPointAxis<Point>>
        > = 0
    >
    decltype(auto) pointAxis(Point&& point, integer axis)
    {
        return std::forward<Point>(point)[axis];
    }

}

namespace Pastel
{

    // Coordinates by point(i)

    template <
        typename Point,
        typename = decltype(std::declval<Point>()((integer)0))>
    struct Point_HasMemberCall_Test {};

    template <typename Type>
    using Point_HasMemberCall = 
        Compiles<Point_HasMemberCall_Test, Type>;

    template <
        typename Point,
        Requires<
            Point_HasMemberCall<Point>,
            Not<Point_HasMemberPointAxis<Point>>,
            Not<Point_HasIndexing<Point>>
        > = 0
    >
    decltype(auto) pointAxis(Point&& point, integer axis)
    {
        return std::forward<Point>(point)(axis);
    }

}

namespace Pastel
{
    // Coordinates by being a number.

    template <
        typename Point,
        Requires<
            Models<Point, Real_Ring_Concept>,
            Not<Point_HasMemberCall<Point>>,
            Not<Point_HasMemberPointAxis<Point>>,
            Not<Point_HasIndexing<Point>>
        > = 0
    >
    decltype(auto) pointAxis(Point&& point, integer axis)
    {
        return std::forward<Point>(point);
    }

}

#endif