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Diffstat (limited to 'Doc/library/weakref.rst')
| -rw-r--r-- | Doc/library/weakref.rst | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/Doc/library/weakref.rst b/Doc/library/weakref.rst index 224f442..1bf6b58 100644 --- a/Doc/library/weakref.rst +++ b/Doc/library/weakref.rst @@ -192,6 +192,35 @@ These method have the same issues as the and :meth:`keyrefs` method of discarded when no strong reference to it exists any more. +.. class:: WeakMethod(method) + + A custom :class:`ref` subclass which simulates a weak reference to a bound + method (i.e., a method defined on a class and looked up on an instance). + Since a bound method is ephemeral, a standard weak reference cannot keep + hold of it. :class:`WeakMethod` has special code to recreate the bound + method until either the object or the original function dies:: + + >>> class C: + ... def method(self): + ... print("method called!") + ... + >>> c = C() + >>> r = weakref.ref(c.method) + >>> r() + >>> r = weakref.WeakMethod(c.method) + >>> r() + <bound method C.method of <__main__.C object at 0x7fc859830220>> + >>> r()() + method called! + >>> del c + >>> gc.collect() + 0 + >>> r() + >>> + + .. versionadded:: 3.4 + + .. data:: ReferenceType The type object for weak references objects. |