> That's true, and Guile and Chicken do accept that notation, but they
> treat the #s as zeros; I can't believe any implementation does anything
> different.  They are not in R[67]RS, and even Scheme 9, which is
> supposed to be a full R4RS implementation, doesn't support them.   I
> doubt if very many programs, if any, actually contain such literals.

Both Chicken and Guile return (exact? 123#) => #f so that number is
probably not distinguishable from the float 123.0. The current language
in SRFI 174 is probably fine.

> Do you know if that "all Schemes installed" Docker image ever get set
> up?  If so I could run another comprehensive test.

Soon. I have a script that can generate single-Scheme Dockerfiles from
<https://github.com/schemedoc/implementation-metadata>. It's almost
ready to publish; we're just working out some kinks in Akku's R7RS
support. It should be fairly easy to extend the generator to output
multi-Scheme containers. A multi-Scheme Dockerfile is just a
concatenation and simple merge of single-Scheme Dockerfiles. There's a
Scheme DSL to write them: <https://akkuscm.org/packages/(dockerfile)/>.

The script will go into the implementation-metadata repo once it's ready
for Akku. I'll notify you.