;; | ---------------------------------------------------------------------------
;; | LI_RepList
;; | ---------------------------------------------------------------------------
;; | Function : Replaces a member of the list at the specified position
;; | Argument : 'Lst'    - The list to operate on.
;; |            'Pos'    - Postion in list after which the new element is to be
;; |                       replaced (starts with 1).
;; |            'Val'    - The new value of the list member
;; | Returns  : The updated list, if 'pos' is greater than the length of the
;; |            list, the function returns nil
;; | Update   : October 13, 1998
;; | e-mail   : rakesh.rao@4d-technologies.com 
;; | Web      : www.4d-technologies.com
;; | ---------------------------------------------------------------------------


(defun LI_RepList (Lst Pos Val / Lst1 Lst2 cnt len )
(setq
	cnt 0
	len (length Lst)
	Lst1 '()
)

(if (and (> Pos 0) (<= Pos len))
(progn
	(repeat (1- Pos)
		(setq
			Lst1 (cons (nth cnt Lst) Lst1)
			cnt (1+ cnt)
		)
	)

	(setq
		Lst1 (cons Val Lst1)
		Lst1 (reverse Lst1)
		cnt Pos
	)

	(if (> len cnt)
	(progn
		(setq Lst2 '())
		(repeat (- len cnt)
			(setq
				Lst2 (cons (nth cnt Lst) Lst2)
				cnt (1+ cnt)
			)
		)
		(setq
			Lst2 (reverse Lst2)
			Lst1 (append Lst1 Lst2)
		)
	))
))
 Lst1
)