teachpacks/audio.ss
(module audio mzscheme
  (require (lib "mred.ss" "mred")
           (file "audio-glue.ss")
           (lib "unit.ss"))
  (provide teachpack@ teachpack^)

  (define (boolean->acl2 b)
    (if b 't '()))

  (define (acl2->boolean a)
    (if (or (equal? a 'nil) (equal? a '())) #f #t))
  
  (define-signature teachpack^ [play-wav])
  (define-unit teachpack@
    (import)
    (export teachpack^)
    (define (play-wav file async)
      (boolean->acl2 (play-sound file (acl2->boolean async))))))