[omniORB] omniORBpy Exception Question (and omniidlexception patch).

[Tres Seaver]

Duncan Grisby wrote:
> 
> Sorry to all the people on the list who don't care about Python. Maybe
> we need an omniORBpy list.
> 
> On Tuesday 28 March, Randy Wiser wrote:
> 
> > I think I agree with you that CORBA.Exception should inherit from
> > exceptions.Exception (as it does now).
> [...]
> 
> Unfortunately, there is a fundamental conflict between the Python
> mapping for CORBA exceptions, and the full use of the
> exceptions.Exception class. exceptions.Exception is defined as:
> 
> class Exception:
>     """Proposed base class for all exceptions."""
>     def __init__(self, *args):
>         self.args = args
> 
>     def __str__(self):
>         if not self.args:
>             return ''
>         elif len(self.args) == 1:
>             return str(self.args[0])
>         else:
>             return str(self.args)
> 
>     def __getitem__(self, i):
>         return self.args[i]
> 
> The big problem is the args data member. Suppose I have an exception
> declared in IDL
> 
>   interface MyException {
>     long args;
>   };
> 
> An instance of this exception will have a data member called args,
> which clashes with args in the exceptions.Exception base class. This
> means that the __str__ and __getitem__ methods won't work.
> CORBA.Exception already overrides the __str__ method; maybe I need to
> provide a __getitem__ method too?  Would that solve your (Randy's)
> problem?
> 
> Maybe the proper fix is to change the Python mapping to use _args
> instead of args in this case.

I think that is the Right Thing (tm) to do here -- treat the problem just like
any other clashe with the implementation language.

> Alternatively, I could try to convince
> Guido to change exceptions.Exception to call its data member
> __args. Since the args member is documented, I don't imagine he'd be
> keen on that...

"That dog won't hunt", as we say here in Texas. :)

-- 
=========================================================
Tres Seaver  tseaver@digicool.com   tseaver@palladion.com