[CM] mark-explode modifications

[cristopher pierson ewing]

So here's my stab at the facility of naming exploded sounds after the
original sound they were created from:

;;;------find-char
(define (find-char string char)
	(do ((position 0)
		 (i 0 (+ i 1)))
		((= i (string-length string)) position)
	  (if (char=? char (string-ref string i))
	  	(set! position i))))

;;;------trim-name
(define (trim-name name)
	(let ((start 0)
		  (end (find-char name #\.)))
	  (substring name start end)))

;;; -------- mark-explode
;;;
;;; write out each section of a file between marks as a separate file

(define (mark-explode snd)
  "(mark-explode) splits a sound into a bunch of sounds based on mark
placements"
  (let ((start 0)
	(file-ctr 0)
	(name (trim-name (short-file-name snd))))
    (for-each
     (lambda (mark)
       (let ((len (- (mark-sample mark) start)))
	 (array->file (format #f "~A-~D.aif" name file-ctr)
		      (channel->vct start len)
		      len (srate) 1)
	 (set! file-ctr (1+ file-ctr))
	 (set! start (mark-sample mark))))
     (caar (marks)))))

I'll try later to work on the problem of choosing an output file type
according to the input file type.  Can one set (default-output-type) from
inside a let statement so that it returns to normal after the let closes
and normal scope is returned?  I'll try to find out.

C

********************************
Cris Ewing
CME and Telehealth Web Services
University of Washington
School of Medicine
Work Phone: (206) 685-9116
Home Phone: (206) 365-3413
E-mail: cewing@u.washington.edu
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