>> * byte-ascii?
>> * char-ascii?
>> * bytevector-ascii?
>> * string-ascii?
>
> I like these better.  Though byte-ascii? suggests it asks a property to a
> given byte, and gives the impression that it only accepts a byte.

Right, I see your point.

> Can be integer-ascii?.

Maybe that is better.

In that case, maybe it would be clear enough if we start the symbols
with "ascii-" as well. Then every procedure in the SRFI would start with
"ascii-" for consistency.

* ascii-integer?
* ascii-char?
* ascii-bytevector?
* ascii-string?

Would this be unambiguous enough?
John, what do you think about these names?

"There are only two hard things in computer science: cache invalidation
and naming things."

("There are two hard problems in computer science: we only have one joke
and it's not funny.")