""" Some simple examples of new style classes that motivate and
introduce the use of properties. """

import math

class Box(object):
    def __repr__(self):
        return "<A box with length:%s, width:%s, area:%s>" % (self.length, self.width, self.area)

class Box1(Box):
    """A rectangle"""
    def __init__(self,l=1,w=1):
        self.length = l
        self.width = w
        self.area = l * w

class Box2(Box):
    """A rectangle with area getter"""
    def __init__(self,l=1,w=1):
        self.length = l
        self.width = w
    def get_area(self):
        return self.length * self.width
    def set_area(self, val=1):
        print "Warning: area is read only!"

class Box3(Box):
    """A rectangle with area property"""
    def __init__(self,l=1,w=1):
        self.length = l
        self.width = w
    def get_area(self):
        return self.length * self.width
    def set_area(self, val=1):
        print "Warning: area is read only!"
    area = property(get_area, set_area)

class Box4(Box):
    """A rectangle with area property"""
    def __init__(self,l=1,w=1):
        self.length = l
        self.width = w
    @property
    def area(self):
        return self.length * self.width
    @area.setter
    def area(self, val=1):
        print "Warning: area is read only!"

class Box5(Box):
    """A rectangle with area property with setter"""
    def __init__(self,l=1,w=1):
        self.length = l
        self.width = w
        self._color = None
    @property
    def area(self):
        return self.length * self.width
    @area.setter
    def area(self, val=1):
        self.length = self.width = math.sqrt(val)
    @property
    def color(self):
        return self._color
    @color.setter
    def color(self, val):
        self._color = val
    @color.deleter
    def color(self):
        del self._color