Как отмечают другие в комментариях, пример кода, который вы используете, это Common LISP, а не AutoLISP (диалект LISP, используемый AutoCAD). Таким образом, такие функции, как str, with-open-file и format не определены в диалекте AutoLISP.
В AutoLISP общий подход будет следующим:
(if (setq des (open "C:\\YourFolder\\YourFile.txt" "w"))
(progn
(write-line "Your text string" des)
(close des)
)
)
прокомментировал это:
;; If the following expression returns a non-nil value
(if
;; Assign the result of the following expression to the symbol 'des'
(setq des
;; Attempt to acquire a file descriptor for a file with the supplied
;; filepath. The open mode argument of "w" will automatically create
;; a new file if it doesn't exist, and will replace an existing file
;; if it does exist. If a file cannot be created or opened for writing,
;; open will return nil.
(open "C:\\YourFolder\\YourFile.txt" "w")
) ;; end setq
;; Here, 'progn' merely evaluates the following set of expressions and
;; returns the result of the last evaluated expression. This enables
;; us to pass a set of expressions as a single 'then' argument to the
;; if function.
(progn
;; Write the string "Your text string" to the file
;; The write-line function will automatically append a new-line
;; to the end of the string.
(write-line "Your text string" des)
;; Close the file descriptor
(close des)
) ;; end progn
;; Else the file could not be opened for writing
) ;; end if