ANSI Common Lisp 22 Printer 22.1 The Lisp Printer 22.1.3 Default Print-Object Methods
220.127.116.11 Printing Other Vectors
If *print-array* is true
and *print-readably* is false,
other than a string or bit vector is printed using
general-vector syntax; this means that information
about specialized vector representations does not appear.
The printed representation of a zero-length vector is #().
The printed representation of a non-zero-length vector begins with #(.
Following that, the first element of the vector is printed.
If there are any other elements, they are printed in turn, with
each such additional element preceded by
a space if *print-pretty* is false,
or whitespace1 if *print-pretty* is true.
A right-parenthesis after the last element
terminates the printed representation of the vector.
The printing of vectors
is affected by *print-level* and *print-length*.
If the vector has a fill pointer,
then only those elements below
the fill pointer are printed.
If both *print-array* and *print-readably* are false,
the vector is not printed as described above,
but in a format (using #<) that is concise but not readable.
If *print-readably* is true,
the vector prints in an implementation-defined manner;
see the variable *print-readably*.
For information on how the Lisp reader parses these "other vectors,"
see Section 18.104.22.168 Sharpsign Left-Parenthesis.