"""
Exercise 9.1 from "A primer on..."
Demonstrate the magic of inheritance by creating
an apparently empty subclass and checking 
its content using the dir function and
the __dict__ attribute.
"""

import numpy as np

class Line:
    def __init__(self, c0, c1):
        self.c0, self.c1 = c0, c1

    def __call__(self, x):
        return self.c0 + self.c1*x

    def table(self, L, R, n):
        """Returner en tabell med n punkter for L <= x <= R."""
        s = ''
        for x in np.linspace(L, R, n):
            y = self(x)
            s += f'{x:12g} {y:12g}\n'
        return s


class Parabola0(Line):
    pass


p = Parabola0(1,1)
print(dir(p))
print(p.__dict__)