# descrip.py
#
# An example of defining a descriptor object.  In this descriptor, functions
# actually store, retrieve, and delete data from the instance dictionary.
# The only odd part is that the descriptor needs to know what name to use
# for these operations.  If you look at the class Foo below, you'll see
# names given to the descriptor object.

class Descriptor(object):
    def __init__(self,name):
        self.name = name
    def __get__(self,instance,cls):
        print "getting", self.name
        return instance.__dict__[self.name]
    def __set__(self,instance,value):
        print "setting", self.name, value
        instance.__dict__[self.name] = value
    def __delete__(self,instance):
        print "deleting", self.name
        del instance.__dict__[self.name]

class Foo(object):
    x = Descriptor("x")
    y = Descriptor("y")

# Example
f = Foo()
f.x = 2
f.y = 3
print f.x
print f.y