Re: RFC 80 (v2) Exception objects and classes for builtins

At 05:27 PM 8/13/00 -0600, Tony Olekshy wrote:
>Peter Scott wrote:
> >
> > Tony Olekshy wrote:
> > >
> > > Peter Scott wrote, in RFC 80 (v2):
> > > >
> > > > =item id
> > > >
> > > > Unique numeric identifier, assigned by perl developers.
> > >
> > > I'm loath to bother everyone with this but to me the id of an
> > > object should be unique to each *instance* of the class.  If we had
> > >
> > >     my $e = Exception->New(id => "ABC.1234");
> > >     my $f = Exception->New(id => "ABC.1234");
> > >
> > > then $e and $f would have the same id, but be different objects.
> >
> > Yes, the implicit registry bothers me too - not for the core: I
> > figure the perl developers can manage a little enumeration class -
> > but for external stuff.  CPAN could conceivably work since they
> > already have a registry for the naming hierarchy, but what about
> > when you want to write an in-house thingy [...]
>
>Sorry I wasn't more clear on this.  I'm just saying that "id" is
>a bad name for this "labelling" field; if it's called "id" then it
>should be guaranteed, by Perl, to be a unique identifier.  So I
>propose calling it "tag" instead.

How about 'code'?  'tag' has other connotations I'd like to avoid.

> > > > Line number exception was thrown at.  File exception was
> > > > thrown in.
> > >
> > > Should this be line thrown at or line constructed at?  Does
> > > anyone care?
>
> > Hmm - what if we made line() and file() return arrays?  Then we'd
> > also like uncaught exceptions that result in program death to at
> > least have the option of a confess() backtrace, and the data would
> > be in the object.
>
>I think the exception constructor should use the constructor's
>invocation point, and the throw operation should independently
>track the location of the throw.  I keep getting lead back the
>concept of the exception unwinding stack, a natural place to
>keep track of the throws.

But they're different things.  Your unwinding stack is a place to keep 
track of rethrown exceptions; mine is a stack backtrace a la confess kept 
in the 'file' and 'line' attributes of an exception.  Each has its own merits.

--
Peter Scott
Pacific Systems Design Technologies