类方法装饰器

 

def printable():
    def wrapper(cls):
        cls.print=lambda self:print(self.content)
        return cls
    return wrapper

@printable() # 先调用生成wrapper Word=wrapper(Word)
class Word:
    def __init__(self,content):
        self.content=content

print(Word.__dict__)
b=Word('bnm\nuiop')
b.print()

 

def printable(cls):
    cls.print=lambda self:print(self.content)
    return cls

@printable # 不加(),隐含调用,传递Word(被装饰 对象) Word=printable(Word)
class Word:
    def __init__(self,content):
        self.content=content

print(Word.__dict__)
b=Word('bnm\nuiop')
b.print()

 

def b(self):
    print('content : {}'.format(self.content))

def bb(cls):
    def wrapper(*args,**kwargs):
        cls.p=b
        ret=cls(*args,**kwargs)
        return ret
    return wrapper

@bb # 经过包装后bbb变成了wrapper函数,此函数执行后返回cls对象
class bbb:
    def __init__(self,content):
        self.content=content
    pass
print(type(bbb),bbb)

v=bbb(999)
print(type(v),v)
v.p()

 

 

 

def printable(cls):
    def _print(self):
        print('content: {}'.format(self.content),'decorator')
    cls.print=_print
    return cls

class Document:
    def __init__(self,content):
        self.content=content

class Word(Document):pass
class Pdf(Document):pass

@printable
class PrintableWord(Word):pass
print(PrintableWord.__dict__)
print(PrintableWord.mro())

pw=PrintableWord('uiop')
pw.print()

@printable
class PrintablePdf(Pdf):pass
print(PrintablePdf.__dict__)
print(PrintablePdf.__mro__)