> Is everything what you call "reader directive" actually a reader directive?No, you're right. The title should be something else. Any suggestions? We could just title it "#! syntax" or "Hash-bang syntax", but it might be nice to group other prefixes besides "#!" together in the same table.
As far as I am concerned, "#!" means "identifier follows", and what the identifier is tells you what it's for. There is no semantics to "#!" at all. (Fortunately for this theory, /bin/sh is a perfectly good identifier in Scheme.)
A quick search didn't turn up reasonable examples of identifiers with prefixes other than #! in Scheme's read syntax, so I followed your suggestions and renamed that section of the registry "Reader #! identifiers" (source file: reader-hash-bang.scm).
