University
of Washington • CSE583 • D. Notkin © 2000
46
reduce
lLots of choices in defining it
–left-to-right
or right-to-left?
–provide
base value or require non-empty input list and symmetric operator?
lRight-to-left, with base value, used on previous slide
l(define
(reduce fn base x)
(if (null? x) base
(fn (car x)
(reduce fn base (cdr x)))))
(if (null? x) base
(fn (car x)
(reduce fn base (cdr x)))))