anchor.diff:    reader)
   
   (defun read-fact-subchunk (reader size)
  +  "Reads fact subchunk of size SIZE from reader"
     (let ((fact (make-fact-subchunk :samples-num (read-bits 32 reader))))
       (if (/= size 4) (error 'wav-error-subchunk
                              :message "Fact subchunk size is not 4. Do not know what to do"
  
positive.code:              :subchunk subchunk))))
  
  (defun read-subchunks (reader)
    (let (chunks)
      (tagbody
       read-subchunks-loop
  
negative.code:   (invoke-restart 'skip-subchunk c))
  
  (defun read-chunk-header (reader)
    "Reads RIFF chunk header"
    (if (/= (bitreader.be-bignum:read-bits 32 reader)
            +wav-id+)
        (error 'wav-error :message "Not a wav stream"))
  