Re: What to do with (time (length L)) proportional to (length L)

Pascal Costanza wrote:

(let* ((temp1 (mapcar #'f1 some-list))
        (temp2 (mapcar #'f2 temp1))
        (temp3 (mapcar #'f3 temp2)))
   (mapcar #'f4 temp3))
 
You could better say:
 
(loop for elem in some-list
       collect (f4 (f3 (f2 (f1 elem)))))

(map (~> abs sqrt list) '(-4 -9 25))

  ===>
((2) (3) (5))

Given:

(define-syntax ->>
  (syntax-rules ()
    [(_ x)  x]
    [(_ x (y ...) z ...)
     (->> (y ... x) z ...)]
    [(_ x y z ...)
     (->> (y x) z ...)]))

(define-syntax ->
  (syntax-rules ()
    [(_ x)  x]
    [(_ x (y more ...) z ...)
     (-> (y x more ...) z ...)]
    [(_ x y z ...)
     (-> (y x) z ...)]))

;; currying
(define-syntax ~>
  (syntax-rules ()
    [(_ func0 func ...)
     (lambda xs (-> (apply func0 xs) func ...))]))