I copied in the actual file contents. It would perhaps be safest to do
some sort of "read the file and splice the contents in," but I'm not
sure how to do that at the moment.
The natural-number? predicate seems to be
unavailable (though there is a remnant of it in the form of
natural-number/c, which is just a contract alias of
exact-nonnegative-integer?). In any case, it surely means
nonnegative integer.
(One might push the envelope here slightly and add
exactness, but this commit does not go that far.)
D. Ben Knoble