Am Mo., 24. Aug. 2020 um 16:59 Uhr schrieb John Cowan <xxxxxx@ccil.org>:

> The actual wording is "Returns #t if obj is an object created by `error` or one
> of an implementation-defined set of objects."  That would, of course, include objects raised by make-codec, if `error` is not used to raise them.

> I see no particular reason to have a specific predicate.

It would make "guard" more specific and the actual exception object
could, at least in principle, contain more information than just a
"message" and the "irritants" of the "error" procedure.