[Python-ideas] Arguments to exceptions

[Mark E. Haase]

On Thu, Jul 6, 2017 at 2:56 PM, Steven D'Aprano <steve at pearwood.info> wrote:

> > Maybe I'm misunderstanding you, but the proposal has a clear example of
> > raising NameError and getting the name attribute from the exception
> > instance:
> >
> >     try:
> >         raise NameError(name=name, template="name '{name}' is not
> defined.")
> >     except NameError as e:
> >         name = e.kwargs['name']
> >         msg = str(e)
> >         ...
>
> What prevents the programmer from writing this?
>
> raise NameError(nym=s, template="name '{nym}' is not defined.")
>
> Or any other keyword name for that matter. Since the exception class
> accepts arbitrary keyword arguments, we have to expect that it could be
> used with arbitrary keyword arguments.
>

I agree completely with your point here, as well as the overall conclusion
that the proposal to change BaseException is a bad idea. I was merely
replying to [what I perceived as] straw manning of the proposal.
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