Thank you for bringing that to my attention!
I think maybe can the interpreter decide whether __class__ etc. should
be added to the environment with regard to how the function is called?
The interpreter does not provide __class__ etc. for plain placement()
calls, but provide them at calls like child().foo() - when the callee
function is named as a class method. Dynamically.
#2/3
Also thanks for the idea of super(type(self), self) - that works! Like this,
class base():
def foo(self) -> None:
print('Base!')
def placement(self) -> None:
super(type(self), self).foo()
class child(base):
def foo(self) -> None:
pass
foo = placement
child().foo()
But in a more complex case where the base class calls also calls super()
this way, it runs into an infinite recursion. Like:
|class base(): def foo(self) -> None: print('Base!') def
placement(self) -> None: super(type(self), self).foo() class
child(base): def foo(self) -> None: pass foo = placement class
child2(child): def foo(self) -> None: pass foo = placement
child2().foo()|
||
#3/3
I also found it interesting that there are different results from
rebinding a class method with a function defined outside the class, and
with a function defined inside the class. Version 1 and version 2
results in the same error message:
class base:
def foo(self) -> None:
print('Base!')
class child(base):
def foo(self) -> None:
super().foo()
class another(base):
foo = child.foo
another().foo()
Version 2:
class base:
def foo(self) -> None:
print('Base!')
class child(base):
def foo(self) -> None:
print('Child!')
def placement(self) -> None:
super().foo()
foo = placement
class another(base):
foo = child.foo
another().foo()
which all result in a mysterious
TypeError: super(type, obj): obj must be an instance or subtype of type
I guess there is an argument issue. Maybe foo() is called as a classmethod?
While this,
class base:
def foo(self) -> None:
print('Base!')
def placement(self) -> None:
super().foo()
class child(base):
def foo(self) -> None:
print('Child!')
foo = placement
class another(base):
foo = child.foo
another().foo()
Results in the familiar RuntimeError: super(): __class__ cell not found.
Thank you!
Yua
On 28/07/2021 11:29, Christopher Barker wrote:
How would the interpreter know which
Class the rebound “belonged” to?
For example, that same function could be added to two different
classes— then what would super() do?
BTW, the Python 2 style of calling súper with the class and instance
as arguments might work in the case :-)
As an experiment, try adding the placement method to a different class
altogether and see what you get.
class another:
foo = child.placement
-CHB
On Tue, Jul 27, 2021 at 8:16 PM Yua <unch...@163.com
<mailto:unch...@163.com>> wrote:
For example, the following code would report an error:
class base():
def foo(self) -> None:
print('Base!')
def placement(self) -> None:
super().foo()
class child(base):
def foo(self) -> None:
pass
foo = placement
child().foo()
RuntimeError: super(): __class__ cell not found
However, it would be OK if `placement` is defined inside the class:
class base():
def foo(self) -> None:
print('Base!')
class child(base):
def placement(self) -> None:
super().foo()
def foo(self) -> None:
pass
foo = placement
child().foo()
which prints:
Base!
I think it would be natural if those functions that was defined
outside
a class, but then rebound into a class, can see magic variables like
__class__ that are only shared by those functions defined inside a
class.
Thank you!
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