write-char character &optional output-stream => character
character—a character.
output-stream – an output stream designator. The default is standard output.
write-char outputs character to output-stream.
(write-char #\a)
|> a
=> #\a
(with-output-to-string (s)
(write-char #\a s)
(write-char #\Space s)
(write-char #\b s))
=> "a b"
The output-stream is modified.
*standard-output*, *terminal-io*.
read-char , write-byte ,