[pro] Some error/condition standardization anyone?

[Marco Antoniotti]

On Jun 27, 2011, at 19:26 , Steve Haflich wrote:

> > Marco Antoniotti wrote:
> >
> > > Now, this is a specific case for me: having a consistent
> > > READER-ERROR-BECAUSE-THERE-IS-NO-SUCH-PACKAGE-THAT-THE-SYSTEM-KNOWS
> > > error signaled would simplify some code writing.
> 
> I agree with the sentiment, what is the specific proposal may need more work.

Of course... this is jut one example.  There may be other cases, plus unexplored ones: FILE-ERROR is rather underspecified, so are PARSE-ERROR and PROGRAM-ERROR.  I'd like to see a discussion started....

> Would you want this same condition to be signaled for this form?
> 
> (defpackage :foo
>   (:use :not-yet-loaded))
> 
> That's an error, but not a reader error the way reading not-yet-loaded:bar would be. Still, it would be nice if these shared a common superclass because what the application might want to do to handle would be the same.

These would both be PACKAGE-ERRORs, but different

> Unfortunately, the condition system does not portably support multiple inheritance.

Yes, I'll grant you that and see where you are going.   This is another CDR:  The Condition system should use the CLOS algorithm to determine/use/offer multiple inheritance derived properties.

Cheers

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Marco Antoniotti, Associate Professor				tel.	+39 - 02 64 48 79 01
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