fork download
copy 
  1. ;; (import (chicken string))
  2. ;; (import (chicken format))
  3. (define (drop-while pred clist)
  4.   (if (or (null? clist) (not (pred (car clist))))
  5.       clist
  6.       (drop-while pred (cdr clist))))
  7. (define cons*
  8.   (case-lambda
  9.    (() (cons))
  10.    ((a) (cons a))
  11.    ((a b) (cons a b))
  12.    ((a b c) (cons a (cons b c)))
  13.    ((a b c d) (cons a (cons b (cons c d))))
  14.    ((a b c d e) (cons a (cons b (cons c (cons d e)))))
  15.    (xs (let ((xs (reverse xs))) (foldl (flip cons) (car xs) (cdr xs))))))
  16. (define (f s)
  17.   (define (aux acc cs)
  18.     (if (null? cs)
  19.         acc
  20.         (let ((c (car cs)) (cs (cdr cs)))
  21.           (if (eq? c #\ )
  22.               (aux (cons* c c c c acc) (drop-while (cut eq? c <>) cs))
  23.               (aux (cons c acc) cs)))))
  24.   (reverse-list->string (aux '() (string->list s))))
  25. (define (g s)
  26.   (format #t "\"~A\" -> \"~A\"~%" s (f s)))
  27. (g "a b     c")
  28. (g " a ")
  29. (g "  a")
  30. (g "a  ")
  31. (g " ")
  32. (g "")
  33.  
Success #stdin #stdout 0.02s 8020KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
"a b     c" -> "a    b    c"
" a " -> "    a    "
"  a" -> "    a"
"a  " -> "a    "
" " -> "    "
"" -> ""
https://ideone.com/SlkO0l
language:
Scheme (chicken 4.13)
created:
8 days ago
visibility:
secret

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!