I took it to be part of the definition of these functions (other than ascii?) that it's an error to apply them to non-ASCII characters, but I see that's not actually true. Perhaps it should be? Consider that (number? 'foo) returns #f, but (even? 'foo) is an error.
>> This is just the negation of ascii-control?, and traditionally Scheme
>> doesn't do these [...] I would propose simply dropping it
>
> lol, you're right. Let's drop it. Perfect.
The only problem is that (complement ascii-control?) would keep
non-ASCII characters. A big part of the point of ascii-graphic? is that
it not only keeps ASCII graphic characters, but also drops non-ASCII
characters.
Would ascii-non-control? (as another name for the same thing) be too fancy?