> If you interpret "returning a value corresponding to how many
> non-keyword arguments are allowed (assuming no keywords arguments are
> required)" in this way, it is fine.
>
> But you can not specify it this way if the sample implementation given
> in SRFI 191 shall be a faithful one (which it really should!).

The trouble comes from a more fundamental level: with the portable 171
implementation, the Scheme implementation itself cannot distinguish
between keyword arguments and rest arguments. Keyword args then look
like a rest arg to the interpreter/compiler, and any introspection
facilities will also be confused about the matter.

I don't think the problem is worth working around, since implementing
proper keyword arguments natively is likely to be no more difficult than
making workarounds. And the result is likely to be faster and more reliable.