python descriptor example

test.py

class Desc(object):
    def __get__(self, obj, klass):
        return lambda x: x+1

class Desc2(object):
    def __get__(self, obj, klass):
        print "getting from Desc2"
        return lambda: obj.name + " guo" 

class A(object):

    # def add_surname(f):
    #     def wrapper(self, surname):
    #         return f(self) + surname
    #     return wrapper

    # @add_surname
    # def getname(self):
    #     return self.name

    def __init__(self, name):
        self.name = name

    adder = Desc()

    show_name = Desc2()

    # def __get__(self, obj, objtype):
    #     print "retrieving A instance value"
    #     return self.name

    # def __set__(self, obj, value):
    #     print "setting A instance value"

    # title = "ceo"

a = A("josh")
a.show_name = "yes"
del a.show_name
print a.show_name()
# print a.adder(2)
# a.__dict__['show_name'] = 'something'
# print a.show_name
# print a.show_name()

# desc = A.__dict__['show_name']
# print desc.__get__(a, A)()



# class B:
#     value = A("josh")

# a = A("josh").getname('guo')
# print a

    
# print A("josh").title
# a = A()
# print aglobal name 'self' is not defined.name('yo')
# print a
# b = B()
# print b.value

# class RevealAccess(object):
#     """A data descriptor that sets and returns values
#        normally and prints a message logging their access.
#     """

#     def __init__(self, initval=None, name='var'):
#         self.val = initval
#         self.name = name

#     def __get__(self, obj, objtype):
#         print 'Retrieving', self.name
#         return self.val

#     def __set__(self, obj, val):
#         print 'Updating', self.name
#         self.val = val

# class MyClass(object):
#     x = RevealAccess(10, 'var "x"')
#     y = 5

# m = MyClass()
# print m.x