info r5rs

7.1.2 External representations

<Datum> is what the read procedure (section see section Input) 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>*)