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# test scoping rules that involve a class
# the inner A.method should be independent to the local function called method
def test1():
def method():
pass
class A:
def method():
pass
print(hasattr(A, "method"))
print(hasattr(A(), "method"))
test1()
# the inner A.method is a closure and overrides the local function called method
def test2():
def method():
return "outer"
class A:
nonlocal method
def method():
return "inner"
print(hasattr(A, "method"))
print(hasattr(A(), "method"))
return method() # this is actually A.method
print(test2())
# a class body will capture external variables by value (not by reference)
def test3(x):
class A:
local = x
x += 1
return x, A.local
print(test3(42))
# assigning to a variable in a class will implicitly prevent it from closing over a variable
def test4(global_):
class A:
local = global_ # fetches outer global_
global_ = "global2" # creates class attribute
global_ += 1 # updates local variable
return global_, A.local, A.global_
global_ = "global"
print(test4(42), global_)
# methods within a class can close over variables outside the class
def test5(x):
def closure():
return x
class A:
def method():
return x, closure()
closure = lambda: x + 1 # change it after A has been created
return A
print(test5(42).method())
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