ms.rkt - Racket scripting

#! /usr/bin/env racket
#lang racket

(define files
  (filter
   (lambda (e) (regexp-match? #rx"[^-ms]\\.csv" e))
   (directory-list (current-directory))))

;; (stdin stdout) now point to (in out)
(define (with-in-out-files proc in out)
  (with-input-from-file in
    (lambda ()
      (with-output-to-file out proc  #:mode 'text #:exists 'replace))))

(define (replace-dot-in-file in)
  (define (dot->comma)
    (for ([l (in-lines)])
      (printf "~a\n"   (regexp-replace #rx"\\." l ","))))
  (define (out-filename file suffix)
    (define file-ext  (regexp-split #rx"\\." file))
    (string-append (first file-ext) suffix "." (second file-ext)))
  (with-in-out-files dot->comma in (out-filename in "-ms")))

(time (for-each replace-dot-in-file files))