Functions :: Scheme
Variadic Functions
Variadic means that the function has no definite arity and the function can take a different number of arguments each time it is called.
variadic sum function example
;;;;
;; sum :: Num... -> Num
;;
;; Takes zero or more numeric arguments and returns their sum.
;;
;; As 0 (zero) is the identity of addition, this function returns 0 if
;; no arguments are provided.
;;
(define (sum . args)
(let go ((lst args) (acc 0))
(cond
((null? lst) acc)
(else (go (cdr lst) (+ (car lst) acc))))))usage
(sum) ;=> 0 (sum 7) ;=> 7 (sum 1 2) ;=> 3 (sum 1 2 3 4 5) ;=> 15