I guess as Scheme language lawyer I'm in the best position:

_ banned explicitly in R6RS

$ OK

@ banned in R[567] in initial position, optional

= OK

? OK

*** OK

... OK because a peculiar identifier

___ problematic, hard to read, but optional

..1 invalid in R6RS because it begins with a character used in numbers

..= ditto

..* = ditto

In short, _, @, ..1, ..=, ..* and probably ___ need replacement.

On Thu, Aug 20, 2020 at 1:36 AM Marc Nieper-Wißkirchen <xxxxxx@nieper-wisskirchen.de> wrote:

Am Mi., 19. Aug. 2020 um 23:17 Uhr schrieb Felix Thibault <xxxxxx@gmail.com>:
There are a couple of things missing (..= and ..*) but what those all turn out to be is up in the air right now so I was going to wait until I was sure how the syntax would end up before I told you what it was. I'll also try to follow along with what's going on here and for now schedule the refactoring to use SRFI-206 for the last draft.

Okay, this makes sense if you compile a consolidated list at some point after everything is no more in flux.
Marc