"(unless COND BODY...): if COND yields nil, do BODY, else return nil."
(cons 'if (cons cond (cons nil body))))
+;; imported from Emacs 20.3.
+(defun-maybe last (x &optional n)
+ "Return the last link of the list X. Its car is the last element.
+If X is nil, return nil.
+If N is non-nil, return the Nth-to-last link of X.
+If N is bigger than the length of X, return X."
+ (if n
+ (let ((m 0) (p x))
+ (while (consp p)
+ (setq m (1+ m) p (cdr p)))
+ (if (<= n 0) p
+ (if (< n m) (nthcdr (- m n) x) x)))
+ (while (cdr x)
+ (setq x (cdr x)))
+ x))
+
(defmacro-maybe save-current-buffer (&rest body)
"Save the current buffer; execute BODY; restore the current buffer.
Executes BODY just like `progn'."
(and (buffer-name (, temp-buffer))
(kill-buffer (, temp-buffer))))))))
-;; imported from Emacs 20.3.
-(defun-maybe last (x &optional n)
- "Return the last link of the list X. Its car is the last element.
-If X is nil, return nil.
-If N is non-nil, return the Nth-to-last link of X.
-If N is bigger than the length of X, return X."
- (if n
- (let ((m 0) (p x))
- (while (consp p)
- (setq m (1+ m) p (cdr p)))
- (if (<= n 0) p
- (if (< n m) (nthcdr (- m n) x) x)))
- (while (cdr x)
- (setq x (cdr x)))
- x))
+(defmacro-maybe combine-after-change-calls (&rest body))
;; imported from Emacs 20.3. (cl function)
(defun-maybe butlast (x &optional n)