[Python-projects] Type inference not working?

[Maarten ter Huurne]

Aurélien Campéas <aurelien.campeas at logilab.fr> wrote on 2008-01-23 06:45:11
PM:

> On Wed, Jan 23, 2008 at 06:48:22PM +0100, Maarten ter Huurne wrote:
> > I wrote on 2008-01-23 06:27:07 PM:
> >
> > [Lotus Notes ate my whitespace, here is the proper code layout, I hope]
> >
> > > ===
> > > class SomeClass(object):
> > >
> > >     def __m(self):
> > >         pass
> > >
> > >     SomeClass().__m()
> > > ===
> >
>
> Hi Marteen,
>
> did you actually execute that code ?

I executed an earlier version, but then I simplified it a bit more and
forgot to execute it again... :(

This is the earlier version, it executes correctly and it triggers the same
warning:

===
class SomeClass(object):

    def __m(self):
        pass

    @staticmethod
    def s():
        SomeClass().__m()

SomeClass.s()
===

The way I want to use it is by having a factory method like this:
===
    @staticmethod
    def create(data):
        instance = SomeClass()
        instance.__setSomething(data)
        return instance
===

I want to have several ways of instantiating the same class and doing it
all using different constructor arguments would be messy.

syt at logilab.fr wrote on 2008-01-23 07:09:22 PM:

> huum, I'm not sure about what you're trying to acheive and what
> behaviour you would expect. Here is an exemple of what's ok and what's
> not (using a private static method since this is the worst case, but it
> could be a class/instance method as well) ::
>
> class SomeClass(object):
>
>     @staticmethod
>     def __m():
>         pass
>
>     def method(self):
>         # calling private method within the class is ok
>         self.__m()
>
>     @classmethod
>     def clsmethod(cls):
>         # calling private method within the class is ok
>         cls.__m()
>
>     @staticmethod
>     def statmethod():
>         # calling private method within the class is ok
>         SomeClass.__m()
>
> class AnotherClass(object):
>     @staticmethod
>     def statmethod():
>         # calling private method from another class is not ok
>         SomeClass.__m()
>
> # calling private method on an instance is not ok, and that's right
> SomeClass().__m()
>
>
> Executing pylint on this produce ::
>
>   W0212: 26:AnotherClass.statmethod: Access to a protected member __m of
a
>   client class
>   W0212: 29: Access to a protected member __m of a client class
>
> which is what was expected (for me at least ;)

What I'd like to do is call a private instance method from a static method
in the same class. This is flagged as a warning, which could mean:
- PyLint considers this as something that is not OK (why?)
- PyLint doesn't know that the instance is of the same class that the
static method belongs to (my guess)

Bye,
            Maarten
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