[编程交流] findfile() vs open()

(open filename)

; First create a ""My_F2L2F_Example.txt" file and place it within trusted acad path _$ (List->File "My_F2L2F_Example.txt" '("Hello," "It's me" "the Grrr guy" "from CADtutor.") )"C:\\Users\\Grrr\\desktop\\trusted acad path\\My_F2L2F_Example.txt"_$ (File->List "C:\\Users\\Grrr\\desktop\\trusted acad path\\My_F2L2F_Example.txt")("Hello," "It's me" "the Grrr guy" "from CADtutor.")_$ (File->List (List->File "My_F2L2F_Example.txt" '("This" "is" "entirely new" "content" "that has" "been writen" "and returned.") ))("This" "is" "entirely new" "content" "that has" "been writen" "and returned."); (List->File "My_F2L2F_Example.txt" '("Hello," "It's me" "the Grrr guy" "from CADtutor.") ); find_what - can be a filename with extension or a full filepath with filename and extension, i.e.: "Example.txt" or "C:\\Users\\Documents\\Example.txt"; L - list of strings(defun List->File ( find_what L / find desc ) (if   (and                                            ; wrap all evaluations, using (and) so the program will stop on the first evaluation that returned nil     L (listp L)                                   ; make sure that a list is provided, and its a list, since (listp nil) -> T     (vl-every '(lambda (x) (eq 'STR (type x))) L) ; make sure that every item inside the list is a string     (setq find (findfile find_what))              ; find the fine, should return the file's path as a string [sTR]     (setq desc (open find "w"))                   ; obtain file's descriptor (open for writing), using the file's path     (mapcar '(lambda (x) (write-line x desc)) L)  ; write each item of the list as a new line, inside the file     (and desc (not (close desc)))                 ; close the file's descriptor, (close desc) -> nil ; so we use: (not (close desc)) -> T   ); and   find                                            ; if everything is ok, return the file path we have found, else nil ); if ); defun List->File; (File->List "My_F2L2F_Example.txt"); find_what - can be a filename with extension or a full filepath with filename and extension, i.e.: "Example.txt" or "C:\\Users\\Documents\\Example.txt"(defun File->List ( find_what / find desc row L ) (and                                   ; wrap all evaluations, using (and) so the program will stop on the first evaluation that returned nil   (setq find (findfile find_what))     ; find the fine, should return the file's path as a string [sTR]   (setq desc (open find "r"))          ; obtain file's descriptor (open for reading), using the file's path   (progn                               ; wrap the following (while) loop inside a (progn), cause it would return nil     (while (setq row (read-line desc)) ; using a loop obtain the 'nth' row, until an end-of-line marker is encountered       (setq L (cons row L))            ; collect every row in a list     ); while      (and desc (not (close desc)))      ; close the file's descriptor, (close desc) -> nil ; so we use: (not (close desc)) -> T ; this also is used to return true for the (progn) expression   ); progn ); and (reverse L)                            ; reverse the list with collected rows, to return properly, (reverse nil) doesn't error out); defun File->List