Accessing 'mangled' class attrbutes

[Gerard Flanagan]

Steve Juranich wrote:
> Gerard Flanagan wrote:
>
> > I tried that Steve but it didn't work, and i don't think I can do what
> > I want in any case.  There is no method '__write' in the base class, it
> > is only declared as an instance attribute in the constructor, like so:
> >
> >     def __init__(self, file, encoding="us-ascii"):
> >         ...
> >         self.__write = file.write
> >         ...
> >
> > I tried putting  '__write = None' at the class level (in the base class
> > XMLWriter) but then, although '_XMLWriter__write' appears in
> > 'dir(HtmlWriter)', I get  'NoneType is not callable'.
> >
> > I also tried 'def __write(self, text) : pass ' in the base class, but
> > then the code runs but doesn't write the text I want -  and anyway, if
> > I'm going to change the base class, then i may as well just add the
> > 'write_raw' method to the base directly!
> >
> > It's just some toy code at any rate, and I've learnt something new!
> > Thanks for your reply.
> >
> > Gerard
> >
>
> Make sure you're calling the super's constructor before you try and access
> the mangled member.  Then (I forgot this part), you can just call the
> mangled member from `self'.  Example follows.
>
> <foo.py>
> class A(object):
>     def __init__(self):
>         self.__foo = lambda x, y : x + y
>
> class B(A):
>     def __init__(self, x, y):
>         # Make sure you're calling the super's constructor first.
>         super(B, self).__init__()
>         self.sum = self._A__foo(x, y)
> </foo.py>
>
> >>> import foo
> >>> b = foo.B(3, 4)
> >>> b.sum
> 7
> >>>
>
> --
> Steve Juranich
> Tucson, AZ
> USA


It's all becoming clear!  Yes, calling the base constructor was all I
needed to do:

class HtmlWriter(elementtree.SimpleXMLWriter.XMLWriter, object):

    def __init__(self, file):
        super( HtmlWriter, self).__init__(file)

    def write_raw(self, text):
        self.flush()
        self._XMLWriter__write(text)

-works a charm. Appreciate your help Steve, thanks again.

Gerard