Package: Emacs
Version: 31.0.50


I think we should clean up our use of "condition objects", i.e. those
objects created (internally) by `signal` and then passed back to ELisp
via the VAR argument of `condition-case`.

I manually re-ordered the patch so that it starts with `subr.el` where
you can see the new definitions I suggest, and then the rest of the
patch illustrates how they'd be used.

The patch is not intended to be installed as-is because it changes some
files which need to preserve backward compatibility with Emacsen without
the new API.

Also the patch lacks the "main" change which would be to replace the
(almost 100) occurrences of

    (signal (car FOO) (cdr FOO))

with

    (condition-resignal FOO)

Beside whether we want to do this or not, there is another question
about naming: currently we use "condition" in some places (e.g. in
`condition-case`) but we use "error" in others (e.g. `define-error` and
`error-message-string`).  I chose to use "condition" in the patch below,
but I don't have a strong opinion on that choice, so I could go with
"error" if that's what other prefer.  If we keep "condition" there's the
subsidiary question whether we should add aliases for `define-error` and
`error-message-string`.


        Stefan