teachpacks/audio.scm
(module audio mzscheme
  (require (lib "mred.ss" "mred")
           (file "audio-glue.scm")
           (lib "unit.ss"))
  (provide teachpack@ teachpack^)
  
  (define-signature teachpack^ [play-wav])
  (define-unit teachpack@
    (import)
    (export teachpack^)
    (define (play-wav file async) (if (playx file async) 't '()))))