7.1.2 External representations

<Datum> is what the read procedure (section 6.6.2) successfully parses. Note that any string that parses as an <expression> will also parse as a <datum>.

<datum> ---> <simple datum> | <compound datum>

<simple datum> ---> <boolean> | <number> | <character> | <string>
                  | <symbol>

<symbol> ---> <identifier>

<compound datum> ---> <list> | <vector>

<list> ---> (<datum>*) | (<datum>+ . <datum>) | <abbreviation>

<abbreviation> ---> <abbrev prefix> <datum>

<abbrev prefix> ---> ' | ` | , | ,@

<vector> ---> #(<datum>*)