+(define-public ((make-accidental-rule octaveness lazyness) context pitch barnum measurepos)
+ "Creates an accidental rule that makes its decision based on the octave of the note
+ and a laziness value.
+ octaveness is either 'same-octave or 'any-octave and defines whether the rule should
+ respond to accidental changes in other octaves than the current. 'same-octave is the
+ normal way to typeset accidentals - an accidental is made if the alteration is different
+ from the last active pitch in the same octave. 'any-octave looks at the last active pitch
+ in any octave.
+ lazyness states over how many bars an accidental should be remembered.
+ 0 is default - accidental lasts over 0 bar lines, that is, to the end of current measure.
+ A positive integer means that the accidental lasts over that many bar lines.
+ -1 is 'forget immediately', that is, only look at key signature.
+ #t is forever."
+ (let ((keysig (ly:context-property context 'localKeySignature)))
+ (ly:find-accidentals-simple keysig pitch barnum lazyness octaveness)))
+
+(define (key-entry-notename entry)
+ "Return the pitch of an entry in localKeySignature. The entry is either of the form
+ '(notename . alter) or '((octave . notename) . (alter barnum . measurepos))."
+ (if (number? (car entry))
+ (car entry)
+ (cdar entry)))
+
+(define (key-entry-octave entry)
+ "Return the octave of an entry in localKeySignature (or #f if the entry does not have
+ an octave)."
+ (and (pair? (car entry)) (caar entry)))
+
+(define (key-entry-bar-number entry)
+ "Return the bar number of an entry in localKeySignature (or #f if the entry does not
+ have a bar number)."
+ (and (pair? (car entry)) (caddr entry)))
+
+(define (key-entry-measure-position entry)
+ "Return the measure position of an entry in localKeySignature (or #f if the entry does
+ not have a measure position)."
+ (and (pair? (car entry)) (cdddr entry)))
+
+(define (key-entry-alteration entry)
+ "Return the alteration of an entry in localKeySignature."
+ (if (number? (car entry))
+ (cdr entry)
+ (cadr entry)))
+
+(define-public (find-pitch-entry keysig pitch accept-global accept-local)
+ "Return the first entry in keysig that matches the pitch.
+ accept-global states whether key signature entries should be included.
+ accept-local states whether local accidentals should be included.
+ if no matching entry is found, #f is returned."
+ (if (pair? keysig)
+ (let* ((entry (car keysig))
+ (entryoct (key-entry-octave entry))
+ (entrynn (key-entry-notename entry))
+ (oct (ly:pitch-octave pitch))
+ (nn (ly:pitch-notename pitch)))
+ (if (and (equal? nn entrynn)
+ (or (and accept-global (equal? #f entryoct))
+ (and accept-local (equal? oct entryoct))))
+ entry
+ (find-pitch-entry (cdr keysig) pitch accept-global accept-local)))
+ #f))
+
+(define-public (neo-modern-accidental-rule context pitch barnum measurepos)
+ "an accidental rule that typesets an accidental if it differs from the key signature
+ AND does not directly follow a note on the same staff-line.
+ This rule should not be used alone because it does neither look at bar lines
+ nor different accidentals at the same notename"
+ (let* ((keysig (ly:context-property context 'localKeySignature))
+ (entry (find-pitch-entry keysig pitch #t #t)))
+ (if (equal? #f entry)
+ (cons #f #f)
+ (let* ((global-entry (find-pitch-entry keysig pitch #t #f))
+ (key-acc (if (equal? global-entry #f)
+ 0
+ (key-entry-alteration global-entry)))
+ (acc (ly:pitch-alteration pitch))
+ (entrymp (key-entry-measure-position entry))
+ (entrybn (key-entry-bar-number entry)))
+ (cons #f (not (or (equal? acc key-acc)
+ (and (equal? entrybn barnum) (equal? entrymp measurepos)))))))))
+
+(define-public (teaching-accidental-rule context pitch barnum measurepos)
+ "an accidental rule that typesets a cautionary accidental
+ if it is included in the key signature AND does not directly follow
+ a note on the same staff-line."
+ (let* ((keysig (ly:context-property context 'localKeySignature))
+ (entry (find-pitch-entry keysig pitch #t #t)))
+ (if (equal? #f entry)
+ (cons #f #f)
+ (let* ((global-entry (find-pitch-entry keysig pitch #f #f))
+ (key-acc (if (equal? global-entry #f)
+ 0
+ (key-entry-alteration global-entry)))
+ (acc (ly:pitch-alteration pitch))
+ (entrymp (key-entry-measure-position entry))
+ (entrybn (key-entry-bar-number entry)))
+ (cons #f (not (or (equal? acc key-acc)
+ (and (equal? entrybn barnum) (equal? entrymp measurepos)))))))))
+