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kaka19ace/test_metaclass.py

Created November 3, 2015 16:35
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  1. kaka19ace created this gist Nov 3, 2015.
    103 changes: 103 additions & 0 deletions test_metaclass.py
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,103 @@
    #!/usr/bin/env python
    # -*- coding: utf-8 -*-
    #
    # @file test_metaclass.py
    # @author kaka_ace <[email protected]>
    # @date Nov 03 2015
    # @brief
    #


    class MyMeta(type):
    def __new__(cls, name, bases, d):
    print("-------------- meta new --------------")
    print(cls)
    print(name)
    print(bases)
    print(d)
    cls = type.__new__(cls, name, bases, d)
    return cls

    def __init__(cls, name, bases, d):
    print("-------------- meta init --------------")
    print(cls)
    print(name)
    print(bases)
    print(d)
    super(MyMeta, cls).__init__(name, bases, d)

    def __call__(cls, *args, **kwargs):
    print("-------------- meta call --------------")
    print(cls)
    print(args)
    print(kwargs)
    return type.__call__(cls, *args, **kwargs)


    class Base(metaclass=MyMeta):
    STATUS = 1

    def __new__(cls, *args, **kwargs):
    print("-------------- Base new --------------")
    print(cls)
    print(args)
    print(kwargs)
    return super(Base, cls).__new__(cls) # object 不需要加参数啦

    def __init__(self, *args, **kwargs):
    print("-------------- Base init --------------")
    print(self)
    print(args)
    print(kwargs)
    super(Base, self).__init__()

    # 此时输出:
    # meta new Base
    # meta init Base


    class Derive(Base):
    D_STATUS = 1

    def __new__(cls, *args, **kwargs):
    print("-------------- Derive new --------------")
    print(cls)
    print(args)
    print(kwargs)
    return super(Derive, cls).__new__(cls, *args, **kwargs)

    def __init__(self, *args, **kwargs):
    print("-------------- Derive init --------------")
    print(self)
    print(args)
    print(kwargs)
    super(Derive, self).__init__(*args, **kwargs)

    # 此时输出:
    # meta new Derive
    # meta init Derive

    """
    b 实例生成过程:
    meta call
    Base new
    b 实例生成
    b init -> Base init
    """
    b1 = Base(1)


    """
    d 实例生成过程:
    meta call
    Derive new
    Base new
    b 实例生成
    b init -> Derive init -> Base init
    """
    d1 = Derive('a')

    print("-----------------------------")
    # 同 b1, d1
    b2 = Base()
    d2 = Derive()