[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Opaque syntax objects
> From: Michael Sperber <sperber@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
> I guess I didn't catch the drift of your earlier message: Are you
> implying that syntax objects can be opaque, and that CAR and CDR
> should be extended to work on them?
If you would consider it okay for a subtype of the pair type to be
called opaque, then I think yes.
> Does this mean, by transitivity,
> any R5RS procedure that works on lists or pairs should also work on
> syntax objects?
> That's a tall order, and one not every implementor
> might feel comfortable about.
Understood. At least an easily portable implementation is provided, which
should mitigate their pain a little ;-)
I have no illusions that the two big current syntax-case implementors will
adopt it, but it does provide an almost completely backward compatible
superset of "portable syntax-case". Users who are uncomfortable with
car/cdr can happily ignore them.