(Racket 7.0) This program runs in no time:
(define (sum n acc)
(if (> n 0)
(sum (- n 1) (+ acc n))
acc))
(collect-garbage) (collect-garbage) (collect-garbage)
(time (sum 10000000 0))
; cpu time: 47 real time: 57 gc time: 0
; 50000005000000
This slightly modified program runs significantly slower:
(define (sum n acc)
(if (> n 0)
(let ([ans (sum (- n 1) (+ acc n))])
ans)
acc))
(collect-garbage) (collect-garbage) (collect-garbage)
(time (sum 10000000 0))
; cpu time: 1719 real time: 1872 gc time: 1064
; 50000005000000
While the call to `sum` in the second program is not in tail position, I
wonder if this kind of code happens often enough from macro expansion to
benefit from an optimization.
--
You received this message because you are subscribed to the Google Groups
"Racket Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to racket-users+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
