On 10/1/2019 3:37 AM, ast wrote:
The following code is working well and I don't really understand why
def factorial(self, n):
if not n:
return 1
else:
return n * factorial(self, n - 1)
This creates a function that looks up 'factorial' in the global (module)
scope when called.
Dummy = type("DummyObject", (object, ), {"factorial" : factorial})
This creates a reference to the function in the class dict. There is
now one function object with 2 references.
instance = Dummy()
instance.factorial(3)
instance.factorial still looks up 'factorial' in the global scope, and
finds it there. If you delete the global reference after creating the
class, the lookup will fail, as when
6 # correct
The problem is that "factorial" in line
"return n * factorial(self, n - 1)" should not have been found
because there is no factorial function defined in the current
scope.
Yes there is. the 'current' scope always includes globals, and globals
has a reference to the function.
--
Terry Jan Reedy
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