Das deutsche Python-Forum

Code: Alles auswählen

import sys
import dis
import inspect


NO_ATTRIBUTE = object()


class SeparateNamedspacedMeta(type):
    def __new__(cls, name, bases, attributes):
        _methods = {}
        for name, attribute in attributes.iteritems():
            if name.startswith('__') and name.endswith('__'):
                continue
            if inspect.isfunction(attribute):
                _methods[name] = attribute
                attributes[name] = AttributeOrMethodDescriptor(name)
        attributes['_methods'] = _methods
        return type.__new__(cls, name, bases, attributes)


class AttributeOrMethodDescriptor(object):
    def __init__(self, name):
        self.name = name
        self.attribute_value = NO_ATTRIBUTE

    def __get__(self, instance, owner):
        if instance is None or self.attribute_value is NO_ATTRIBUTE:
            return owner._methods[self.name].__get__(instance, owner)
        calling_frame = sys._getframe(1)
        next_opcode = ord(calling_frame.f_code.co_code[calling_frame.f_lasti + 3])
        if dis.opname[next_opcode] == 'CALL_FUNCTION':
            return owner._methods[self.name].__get__(instance, owner)
        return self.attribute_value

    def __set__(self, instance, value):
        self.attribute_value = value

    def __delete__(self, instance):
        self.attribute_value = NO_ATTRIBUTE


class SeparateNamespacedClass(object):
    __metaclass__ = SeparateNamedspacedMeta

    def __init__(self):
        self.spam = 'attribute'

    def spam(self):
        return 'method'


foo = SeparateNamespacedClass()
print SeparateNamespacedClass.spam # <unbound method spam.spam>
print foo.spam # attribute
print foo.spam() # method