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Yeah, I had a feeling the real 'expansion' would be more involved. I didn't know about the lookup in __dict__, that's good to know. I'm reminded of PHP, where
by chriswarbo 8y ago
Yeah, I had a feeling the real 'expansion' would be more involved. I didn't know about the lookup in __dict__, that's good to know.
I'm reminded of PHP, where (at least in version 5.*) we could write:
$myObject->foo = function() { return "hello world"; };
$x = $myObject->foo;
$x(); // Hello world
$myObject->foo(); // Error: no such method 'foo'
(Taken from an old comment https://news.ycombinator.com/item?id=8119419 https://news.ycombinator.com/item?id=8119419 )
- bilboa 8y agoI found the official docs on how python special methods are looked up. https://docs.python.org/3/reference/datamodel.html#special-lookup https://docs.python.org/3/reference/datamodel.html#special-l... Apparently the runtime is even more picky than I showed. The method has to be defined on the object's type, not in the object's instance dictionary. So, really the lookup is something like: if hasattr(type(a), '__add__'): The link I provided explains the rationale for bypassing the instance dictionary and `__getattribute__` method.