+Notes: natural 11 is left from chord if not explicitly specified.
+
+Entry point for the parser.
+"
+ (let* ((flat-mods (flatten-list modifications))
+ (base-chord (stack-thirds (ly:make-pitch 0 4 0) the-canonical-chord))
+ (complete-chord '())
+ (bass #f)
+ (inversion #f)
+ (lead-mod #f)
+ (explicit-11 #f)
+ (start-additions #t))
+
+ (define (interpret-inversion chord mods)
+ "Read /FOO part. Side effect: INVERSION is set."
+ (if (and (> (length mods) 1) (eq? (car mods) 'chord-slash))
+ (begin
+ (set! inversion (cadr mods))
+ (set! mods (cddr mods))))
+ (interpret-bass chord mods))
+
+ (define (interpret-bass chord mods)
+ "Read /+FOO part. Side effect: BASS is set."
+ (if (and (> (length mods) 1) (eq? (car mods) 'chord-bass))
+ (begin
+ (set! bass (cadr mods))
+ (set! mods (cddr mods))))
+ (if (pair? mods)
+ (scm-error 'chord-format "construct-chord" "Spurious garbage following chord: ~A" mods #f))
+ chord)
+
+ (define (interpret-removals chord mods)
+ (define (inner-interpret chord mods)
+ (if (and (pair? mods) (ly:pitch? (car mods)))
+ (inner-interpret (remove-step (+ 1 (ly:pitch-steps (car mods))) chord)
+ (cdr mods))
+ (interpret-inversion chord mods)))
+ (if (and (pair? mods) (eq? (car mods) 'chord-caret))
+ (inner-interpret chord (cdr mods))
+ (interpret-inversion chord mods)))
+
+ (define (interpret-additions chord mods)
+ "Interpret additions. TODO: should restrict modifier use?"
+ (cond ((null? mods) chord)
+ ((ly:pitch? (car mods))
+ (if (= (pitch-step (car mods)) 11)
+ (set! explicit-11 #t))
+ (interpret-additions (cons (car mods) (remove-step (pitch-step (car mods)) chord))
+ (cdr mods)))
+ ((procedure? (car mods))
+ (interpret-additions ((car mods) chord)
+ (cdr mods)))
+ (else (interpret-removals chord mods))))
+
+ (define (pitch-octavated-strictly-below p root)
+ "return P, but octavated, so it is below ROOT"
+ (ly:make-pitch (+ (ly:pitch-octave root)
+ (if (> (ly:pitch-notename root)
+ (ly:pitch-notename p))
+ 0 -1))
+ (ly:pitch-notename p)
+ (ly:pitch-alteration p)))
+
+ (define (process-inversion complete-chord)
+ "Take out inversion from COMPLETE-CHORD, and put it at the bottom.
+Return (INVERSION . REST-OF-CHORD).
+
+Side effect: put original pitch in INVERSION.
+If INVERSION is not in COMPLETE-CHORD, it will be set as a BASS, overriding
+the bass specified.
+
+"
+ (let* ((root (car complete-chord))
+ (inv? (lambda (y)
+ (and (= (ly:pitch-notename y)
+ (ly:pitch-notename inversion))
+ (= (ly:pitch-alteration y)
+ (ly:pitch-alteration inversion)))))
+ (rest-of-chord (remove inv? complete-chord))
+ (inversion-candidates (filter inv? complete-chord))
+ (down-inversion (pitch-octavated-strictly-below inversion root)))
+ (if (pair? inversion-candidates)
+ (set! inversion (car inversion-candidates))
+ (begin
+ (set! bass inversion)
+ (set! inversion #f)))
+ (if inversion
+ (cons down-inversion rest-of-chord)
+ rest-of-chord)))
+ ;; root is always one octave too low.
+ ;; something weird happens when this is removed,
+ ;; every other chord is octavated. --hwn... hmmm.
+ (set! root (ly:pitch-transpose root (ly:make-pitch 1 0 0)))
+ ;; skip the leading : , we need some of the stuff following it.
+ (if (pair? flat-mods)
+ (if (eq? (car flat-mods) 'chord-colon)
+ (set! flat-mods (cdr flat-mods))
+ (set! start-additions #f)))
+ ;; remember modifier
+ (if (and (pair? flat-mods) (procedure? (car flat-mods)))
+ (begin
+ (set! lead-mod (car flat-mods))
+ (set! flat-mods (cdr flat-mods))))
+ ;; extract first number if present, and build pitch list.
+ (if (and (pair? flat-mods)
+ (ly:pitch? (car flat-mods))
+ (not (eq? lead-mod sus-modifier)))
+ (begin
+ (if (= (pitch-step (car flat-mods)) 11)
+ (set! explicit-11 #t))
+ (set! base-chord
+ (stack-thirds (car flat-mods) the-canonical-chord))
+ (set! flat-mods (cdr flat-mods))))
+ ;; apply modifier
+ (if (procedure? lead-mod)
+ (set! base-chord (lead-mod base-chord)))
+ (set! complete-chord
+ (if start-additions
+ (interpret-additions base-chord flat-mods)
+ (interpret-removals base-chord flat-mods)))
+ (set! complete-chord (sort complete-chord ly:pitch<?))
+ ;; If natural 11 + natural 3 is present, but not given explicitly,
+ ;; we remove the 11.
+ (if (and (not explicit-11)
+ (get-step 11 complete-chord)
+ (get-step 3 complete-chord)
+ (= 0 (ly:pitch-alteration (get-step 11 complete-chord)))
+ (= 0 (ly:pitch-alteration (get-step 3 complete-chord))))
+ (set! complete-chord (remove-step 11 complete-chord)))
+ ;; must do before processing inversion/bass, since they are
+ ;; not relative to the root.
+ (set! complete-chord (map (lambda (x) (ly:pitch-transpose x root))
+ complete-chord))
+ (if inversion
+ (set! complete-chord (process-inversion complete-chord)))
+ (if bass
+ (set! bass (pitch-octavated-strictly-below bass root)))
+ (if #f
+ (begin
+ (write-me "\n*******\n" flat-mods)
+ (write-me "root: " root)
+ (write-me "base chord: " base-chord)
+ (write-me "complete chord: " complete-chord)
+ (write-me "inversion: " inversion)
+ (write-me "bass: " bass)))
+ (if inversion
+ (make-chord-elements (cdr complete-chord) bass duration (car complete-chord)
+ inversion)
+ (make-chord-elements complete-chord bass duration #f #f))))
+
+
+(define (make-chord-elements pitches bass duration inversion original-inv-pitch)
+ "Make EventChord with notes corresponding to PITCHES, BASS and
+DURATION, and INVERSION."