Am So., 16. Aug. 2020 um 13:29 Uhr schrieb Shiro Kawai <xxxxxx@gmail.com>:
>
> Indeed, native continuation mark support is on my todo list for Gauche.

That's great, I mean, very great news!

> So, your suggestion is upon entering srfi-170 procedure it adds a continuation mark indicating such event, with the procedure name and args, and an error thrower deep in the C routine retrieves such info.  Correct?

Either the adding of the continuation mark happens automatically
whenever a SRFI 170 procedure is entered (so that it can be retrieved
by the thrower), or it is the user who adds this continuation mark as
needed. The latter would be in favor of optimization. If we go this
route, convenience procedures (call/cm PROC ARG ...) and (apply/cm
PROC ARG ...) would be helpful. These procedures add a continuation
mark storing the procedure and the args before calling them.