[CM] Fixed(?) :CMN key signature, bar lines, and accidentals

[Larry Troxler]

I think I got this thing working - here's a modified CMN function that
seems to work for me, 
in case anybody is doing CM to CMN transcriptions or the like. 

Of course this is just a temporary patch because I don't understand how
the accidental notation is actually intended to work. 

Larry

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(in-package cmn)

(defun check-note-for-needed-natural (object current-accidentals
current-key-signature-accidentals current-durations cancel octaves)
  (let ((this-cclass (cclass object))
	(this-sign (note-sign object))
	(tied (and (ties object) (find :right (ties object) :key #'tie-type))))
    (when (not tied)
      (if (aref current-accidentals this-cclass)
	  (if (not this-sign)
	      (if (not (eq (aref current-key-signature-accidentals this-cclass)
			   (aref current-accidentals this-cclass)))
		  (if (not (aref current-key-signature-accidentals this-cclass))
		      (if (not (eq (aref current-accidentals this-cclass) natural))
			  (setf (note-sign object) natural))
		    (setf (note-sign object) (aref current-key-signature-accidentals
this-cclass))))
	    (if (and cancel
		     ;; now look for redundant accidental -- the problem with this
version is that
		     ;;   it will leave in accidentals that are technically redundant
if the same
		     ;;   pitch occurs in a different octave in between, and that
makes (for example)
		     ;;   repeated octave jumps kinda fussy looking.
		     (eq this-sign (aref current-accidentals this-cclass))
		     (/= (aref octaves this-cclass) -1)
		     (= (aref octaves this-cclass) (octave object)))
		(setf (note-sign object) nil)))

	(progn
	  ;;; From Larry Troxler: I don't understand what this form does; I
leave it in 
	  ;;; because for my personal use, it will never get hit. 
	  (if (and (aref current-key-signature-accidentals this-cclass)
		   (not this-sign))
	      (progn
		;; bug fix thanks to Jin S. Choi 3-Nov-96
		;; (setf this-sign natural)
		;; (setf (note-sign object) natural))))
		(setf this-sign (or (aref current-key-signature-accidentals
this-cclass) natural))
		(if (not cancel) (setf (note-sign object) this-sign))))

	  ;;; From Larry Troxler: This seems to fix my problem of accidentals
being redundantly
	  ;;; notated although they are in the current key signature.
	  (if (and cancel
		   this-sign
		   (eq (or (aref current-key-signature-accidentals this-cclass)
natural) this-sign))
	      (setf (note-sign object) nil)))))

    (setf (aref octaves this-cclass) (octave object))
    (setf (aref current-durations this-cclass) 0)
    (setf (aref current-accidentals this-cclass) this-sign)))

(defun cmn-acc-test ()
  (cmn (automatic-naturals t) (redundant-accidentals nil)  staff treble
g-major (meter 4 4)
       cs4 cs4 cs5 cs4 
       fs5 fn5 ef5 fs4
       dn4 ds4 dn4 fs4
       ds4 dn4 dn4 ds4))

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