Re: Attaching context info to an error

[João Távora]

On Fri, Dec 29, 2023 at 6:35 PM Stefan Monnier <monnier@iro.umontreal.ca> wrote:
>
> > That's got no connection with what I wrote.  What I'm asking you to
> > confirm is that you're not contemplating introducing error handling
> > machinery which, during bootstrap, will only work after Lisp code has
> > been loaded.
>
> The idea is:
>
> - In the short term, provide new functions that allow manipulating
>   errors in a way that's independent from their representation
>   (as cons cells).
>   Hopefully this will make the code also more readable in many cases.
>   E.g. (error-resignal ERR) instead of (signal (car ERR) (cdr ERR)).
>
> - In the longer term once enough code has been adapted to use the new
>   functions, we may be able to consider changing the representation of
>   error objects.  Presumably error objects would then be changed from
>
>       (list ERROR-TYPE DATA1 DATA2 ...)
>
>   to something like
>
>       (record ERROR-TYPE DATA1 DATA2 ...)
>
>   This shouldn't require anything tricky during bootstrapping.
>
>   But in any case we're pretty damn far from this.  I'd estimate that we
>   have at least 10 years ahead of us to decide if and how we want to
>   make that change.

I concur.  And maybe, to keep 100% backward compatibility to
current Lisp code, condition-case is AFAIK is the only current
to get at error objects from Lisp, would still get the
good-ol cons  representation for those 10 years, or even forever.

João