GNU Emacs Lisp Reference Manual
1.3.4 Printing Notation
Many of the examples in this manual print text when they are
evaluated. If you execute example code in a Lisp Interaction buffer
(such as the buffer `*scratch*'), the printed text is inserted into
the buffer. If you execute the example by other means (such as by
evaluating the function
eval-region), the printed text is
displayed in the echo area.
Examples in this manual indicate printed text with `-|',
irrespective of where that text goes. The value returned by evaluating
the form (here
bar) follows on a separate line.
(progn (print 'foo) (print 'bar))