Am Sa., 15. Aug. 2020 um 17:03 Uhr schrieb Adam Nelson <xxxxxx@nels.onl>:

> There was some discussion about changing the argument placeholder from `<>` to `_`, or changing the rest-arguments placeholder from `<...>` to `<> ...`; I don't intend to make either of those changes, because I'd prefer to keep consistency across SRFIs where possible, and SRFI 26 already uses `<>` and `<...>`.

Speaking of consistency, SRFI 148 uses "<> ...", so this is equally
consistent. There I made the remark that SRFI 26 probably didn't
choose this clearer notation because at that time it was (impossible?)
to implement.

Using "_" (which looks a bit nicer and is shorter than "<>" and
probably more familiar to users coming from different languages) is
not inconsistent with the usual meaning of "_" in macro patterns.
There "_" stands for an unnamed variable and multiple unnamed
variables are allowed just as in this SRFI.

Moreover, SRFI 156 already uses "_" as a placeholder. So I think you
are almost free about the choice when it comes to consistency. :-) And
in this case, IMHO I would choose the simplest, namely "_" and "_
...".

PS: For your nest macros, the placeholder has a similar status like
the ellipsis in syntax-rules. In order to allow to nest nest macros,
please add an optional placeholder parameter to the nest macros just
as SRFI 46 does for syntax-rules. For the standard placeholder, you
need the free-identifier=? equality test; for an optional one, you
probably need the bound-identifier=? equality test.