类型系统之 MRO.md

类型系统之 MRO

class A:
    pass

class B:
    pass

class C(A, B):
    pass

class D(B, A):
    pass

class E(C, D):
    pass

执行上面的代码会报错:

Traceback (most recent call last):
  File "/home/vvv/Workspace/cpython/mydemo/class_demo.py", line 16, in <module>
    class E(C, D):
TypeError: Cannot create a consistent method resolution
order (MRO) for bases A, B

C3 算法

算法实现

在 CPython 中对应的算法实现是 Objects/typeobject.c 中的 mro_implementation 函数. 先看 参考然后再看算法实现更容易理解.

参考

• https://www.python.org/download/releases/2.3/mro/

• https://en.wikipedia.org/wiki/C3_linearization