Ruby在Python中的“ method_missing”

Ruby在Python中的“ method_missing”

正如其他人提到的那样，在Python中，执行时

o.f(x)

实际上是一个两步 *** 作：首先，获取的

f

属性

o

，然后使用parameter对其进行调用

x

。这是因为没有属性而失败的第一步

f

，并且是调用Python
magic方法的那一步

__getattr__

。

因此，您必须实现

__getattr__

，并且它返回的内容必须是可调用的。请记住，如果您也尝试获取

o.some_data_that_doesnt_exist

，

__getattr__

则将调用相同的名称，并且它不会知道它是“数据”属性还是要寻找的“方法”。

这是返回可调用对象的示例：

class MyRubylikeThing(object):    #...    def __getattr__(self, name):        def _missing(*args, **kwargs): print "A missing method was called." print "The object was %r, the method was %r. " % (self, name) print "It was called with %r and %r as arguments" % (args, kwargs)        return _missingr = MyRubylikeThing()r.hello("there", "world", also="bye")

产生：

A missing method was called.The object was <__main__.MyRubylikeThing object at 0x01FA5940>, the method was 'hello'.It was called with ('there', 'world') and {'also': 'bye'} as arguments