>> I've updated<https://registry.scheme.org/#hash-syntax>  and added the
>> following note: "A quote ' next to an implementation's name means the
>> syntax must be quoted in that implementation."

> The syntax itself does not need to be quoted.  If you want to make it
> a valid Scheme expression, you have to use the quote expression from
> the standard.
>
> In any case, this is not a Chez thing, but an R[56]RS thing; many
> syntactic data (vectors, bytevectors, ...) do not form a valid
> expression.

Chez says "Exception: invalid syntax #&123". So that means "invalid
expression syntax", not "invalid lexical syntax"?

> I don't think your note belongs to this table in the Scheme registry.
> For otherwise, you would need the same note for vectors, bytevectors,
> etc. at least for R[56]RS implementations.

Adding the same note for the vector types would be a helpful reminder
IMHO. The R6 vs R7 vector quoting discrepancy is easily missed, for example.

> Moreover, the table is about lexical syntax and #&123 is a valid
> lexical syntax (in Chez Scheme mode): Just enter (read) at the REPL
> and then enter #&123.

I still find the notes helpful and would like to keep them. Can you
supply a better worded sentence? Something like this perhaps:

"A quote ' next to an implementation's name means the syntax is not
self-evaluating in that implementation, and must be quoted to form a
valid expression."