How to sum a list of numbers in Emacs Lisp?

Question

This works:

(+ 1 2 3)
6

This doesn\'t work:

(+ \'(1 2 3))

This works if \'cl-*\' is loaded:

Answer 1

Linearly recursive function (sum L)

;;
;; sum
;;
(defun sum(list)    
    (if (null list)
        0

        (+ 
            (first list) 
            (sum (rest list))
        )   
    )   
)