# tag: cpp

cdef extern from "curiously_recurring_template_pattern_GH1458_suport.h":

    cdef cppclass Base[T, Derived]:

        Base(T)

        Derived half()

        T calculate()

    cdef cppclass Square[T](Base[T, Square[T]]):

        Square(T)

    cdef cppclass Cube[T](Base[T, Cube[T]]):

        Cube(T)

def test_derived(int x):

    """

    >>> test_derived(5)

    (6.25, 8)

    """

    try:

        square_double = new Square[double](x)

        cube_int = new Cube[int](x)

        return square_double.half().calculate(), cube_int.half().calculate()

    finally:

        del square_double, cube_int