newlispfanclub.alh.net

Posted: **Mon Mar 21, 2005 12:34 pm**

Attempt to made a more alisp compatibel append:

(define (append-nil alist )
	(if alist 
		(begin
		(setq _nlst alist)
		(dolist (_lst (args))(setq _nlst(append _nlst _lst))))
		(begin
		(setq _nlst (list ))
		(dolist (_lst (args))(setq _nlst(append _nlst _lst))))
	))

Code: Select all

> (setq a '(1 2))
(1 2)
> (append-nil a '(3)'(4)'(5))
(1 2 3 4 5)
> (append-nil b '(3)'(4)'(5))
(3 4 5)
>

Any better solution?

Posted: **Mon Mar 21, 2005 1:31 pm**

Use 'apply append' instead of 'dolist':

Code: Select all

(define (append-nil alist)
  (if alist (append alist (apply append (args)))
            (apply append (args))))

Lutz

Posted: **Mon Mar 21, 2005 2:33 pm**

Thanks a lot. I have still the problem, to get the brain more lispisch.
;-)

Posted: **Mon Mar 21, 2005 3:51 pm**

we can make it even shorter:

Code: Select all

(define (append-nil alist)
  (append (if alist alist '()) (apply append (args))))

Lutz

newlispfanclub.alh.net

append with first argument optional nil

append with first argument optional nil