Generator inside a class prevent __del__ ??

[Emmanuel]

Terry Reedy a écrit :

> "Emmanuel" <eastier at free.fr> wrote in message
> news:4085BA96.651D2E4A at free.fr...
> > I run across this problem, and couldn't find any solution (python 2.2.2)
> ...
> > Here, everything is normal...
> > But creating a generator :
>
> You both defined generator function and called it to create generator
> iterator.

Yes, I don't have all the generators vocabulary yet...

>
>
> >
> > Code :
> > ===========
> >
> > >>> class toto:
> >             def __init__(self):
> >                 print "init"
> >                 self.Coroutine = self.Gen()
>
> This creates a reference loop.  Delete this (and correct typo below) and
> 'problem' will disappear.

>
> >             def __del__(self):
> >                 print "del"
> >             def Gen(self):
>
> If you do not really use self in the resulting iterator, define this
> outside of the class without self as a parameter, and problem will
> disappear.

I didn't use self in order to provide a simple example. In my real class, self
is used...

>
>
> >                 yield 1
> >
> > >>> a = toto()
>
> did you mean 'c = toto()'?

Yes, sorry for that...

>
>
> > init
> > >>> c = []
> >                 <--- Nothing there !!!
> > ==============
> >
> > I can't understand why the destructor is not called when a generator is
> > created, and what I should do to have a "correct" behavior.
>
> Either do not create reference loop or break it with del c.Coroutine.
>
> Terry J. Reedy

Thank you very much for your answer, but I'm still not sure I understand it.
If I understand your words right, creating self.Coroutine as an iterator on
the generator function will create a reference on self, so if I want to use a
generator in a class ( and I really want to ), I must delete explicitly the
iterator before I destroy the object.

Trouble is, I _would_ like not to care about the lifetime of the object, and I
don't know where it will be destroyed.
Should I encapsulate this object in another one, like this :

import toto

class TotoCapsule:
    def __init__( self ):
        self.toto = toto.toto()
    def __del__(self):
        del self.toto.Coroutine
        self.toto = None

And use TotoCapsule ?
But it means I have to write a lot of more code to access toto's method.
Is there a pattern I missed to dea l with that ?

Thanks a lot,

Emmanuel