Getting User Input
(READ) returns the next form from standard input.
(READ-LINE) returns a string containing the next line of text from standard input.
To get a line of text as a list, we can use:
(defun get-input-as-list (prompt-string)
(format t "~A~%" prompt-string)
(read-line) ; Swallow & ignore current line.
(read-from-string ;Get a form from a string.
(concatenate ;Combine some sequences,
'string ;result to be a string.
(read-line) ;words in the list