Re: [Traits] Is overwriting __init__ 'viral' ?

On Tue, Apr 10, 2012 at 4:59 PM, David Ohlemacher
<dohlemacher <at> scisol.com> wrote:
> Hi Robert,
>
> That is interesting, but Python: Essential Ref, 4th ed, p 120:
>
>    "If you dont know whether the base class defines __init__(), it is
>    always safe to call it without any arguments because there is always
>    a default implementation that simply does nothing."
>
> That seems to be incorrect.  I tried it and it does fail.  It is not in
> errata either.

That's an extremely confusing and pointless statement. It's wrong, at
least as it is currently worded. If none of the super classes define
an __init__(), then it is safe to call the super class's __init__()
without arguments because it is just object.__init__(), which does
indeed take no argument (and woe betide you if you *do* pass it any
arguments). But if any of those super classes define an __init__()
then you must pass the correct arguments.

You always need to know what you are calling. There is nothing that
will work in all situations.

--

-- 
Robert Kern
Enthought
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