read-files.rkt

;; read from p, return a funny symbol if it fails for some reason
(define (try-read p)
  (with-handlers ([(λ _ #t) (λ (_) 'READ-ERROR-ENCOUNTERED)])
    (read p)))

;; for each racket source file, look for usages of "sort"
(for ([p (in-directory dir)]
      #:when (regexp-match? #rx"\\.rkt" (path->string p)))
  (define file (open-input-file p))
  (set! files (add1 files))
  (let loop! ([next (try-read file)])
    (search-sexp! next)
    (when (not (eof-object? next))
      (loop! (try-read file))))
  (close-input-port file))