I have a python module written in C++, and the C++ code has a few instances
that involve method chaining. I was experimenting with python support for
these methods and I found something odd.
However it seems this is more a python eccentricity than Boost Python,
consider the following code sample.
class Test():
def __init__( self ):
print "Init"
def __del__( self ):
print "Del"
def foo( self ):
print "Foo"
return self
def bar( self ):
print "Bar"
return self
And some sample uses:
>> Test().foo().bar()
Init
Foo
Bar
<__main__.Test instance at 0x2aef40e33998>
>>
Note that __del__ was never called, the object still exists somewhere..
There is another odd thing though, if I repeat the same line, the previous
version gets destroyed and replaced by the new version, but only after the
chain methods are done, eg:
>>> Test().foo().bar()
Init
Foo
Bar
Del <-- Old one, NOT the current instance
<__main__.Test instance at 0x2b72bc78d998>
>>
However if I do:
def Tester():
Test().foo().bar()
# To make sure del is not called by the function returning
while True:
pass
>> Tester()
Init
Foo
Bar
Del
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 4, in Tester
KeyboardInterrupt
>>
That time __del__ was called immediately ( as intended ).
Is there something I should be aware of here? Some sort of difference
between the global instances and ones defined in a function? Can I do
anything so global instances are cleaned up immediately like they are inside
functions?
Thanks
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