+(define (recent-enough? bar-number alteration-def laziness)
+ (or (number? alteration-def)
+ (equal? laziness #t)
+ (<= bar-number (+ (cadr alteration-def) laziness))))
+
+(define (accidental-invalid? alteration-def)
+ "Checks an alteration entry for being invalid.
+
+Non-key alterations are invalidated when tying into the next bar or
+when there is a clef change, since neither repetition nor cancellation
+can be omitted when the same note occurs again.
+
+Returns @code{#f} or the reason for the invalidation, a symbol."
+ (let* ((def (if (pair? alteration-def)
+ (car alteration-def)
+ alteration-def)))
+ (and (symbol? def) def)))
+
+(define (extract-alteration alteration-def)
+ (cond ((number? alteration-def)
+ alteration-def)
+ ((pair? alteration-def)
+ (car alteration-def))
+ (else 0)))
+
+(define (check-pitch-against-signature context pitch barnum laziness octaveness)
+ "Checks the need for an accidental and a @q{restore} accidental against
+@code{localKeySignature}. The @var{laziness} is the number of measures
+for which reminder accidentals are used (i.e., if @var{laziness} is zero,
+only cancel accidentals in the same measure; if @var{laziness} is three,
+we cancel accidentals up to three measures after they first appear.
+@var{octaveness} is either @code{'same-octave} or @code{'any-octave} and
+specifies whether accidentals should be canceled in different octaves."
+ (let* ((ignore-octave (cond ((equal? octaveness 'any-octave) #t)
+ ((equal? octaveness 'same-octave) #f)
+ (else
+ (ly:warning (_ "Unknown octaveness type: ~S ") octaveness)
+ (ly:warning (_ "Defaulting to 'any-octave."))
+ #t)))
+ (key-sig (ly:context-property context 'keySignature))
+ (local-key-sig (ly:context-property context 'localKeySignature))
+ (notename (ly:pitch-notename pitch))
+ (octave (ly:pitch-octave pitch))
+ (pitch-handle (cons octave notename))
+ (need-restore #f)
+ (need-accidental #f)
+ (previous-alteration #f)
+ (from-other-octaves #f)
+ (from-same-octave (assoc-get pitch-handle local-key-sig))
+ (from-key-sig (or (assoc-get notename local-key-sig)
+
+ ;; If no key signature match is found from localKeySignature, we may have a custom
+ ;; type with octave-specific entries of the form ((octave . pitch) alteration)
+ ;; instead of (pitch . alteration). Since this type cannot coexist with entries in
+ ;; localKeySignature, try extracting from keySignature instead.
+ (assoc-get pitch-handle key-sig))))
+
+ ;; loop through localKeySignature to search for a notename match from other octaves
+ (let loop ((l local-key-sig))
+ (if (pair? l)
+ (let ((entry (car l)))
+ (if (and (pair? (car entry))
+ (= (cdar entry) notename))
+ (set! from-other-octaves (cdr entry))
+ (loop (cdr l))))))
+
+ ;; find previous alteration-def for comparison with pitch
+ (cond
+ ;; from same octave?
+ ((and (not ignore-octave)
+ from-same-octave
+ (recent-enough? barnum from-same-octave laziness))
+ (set! previous-alteration from-same-octave))
+
+ ;; from any octave?
+ ((and ignore-octave
+ from-other-octaves
+ (recent-enough? barnum from-other-octaves laziness))
+ (set! previous-alteration from-other-octaves))
+
+ ;; not recent enough, extract from key signature/local key signature
+ (from-key-sig
+ (set! previous-alteration from-key-sig)))
+
+ (if (accidental-invalid? previous-alteration)
+ (set! need-accidental #t)
+
+ (let* ((prev-alt (extract-alteration previous-alteration))
+ (this-alt (ly:pitch-alteration pitch)))
+
+ (if (not (= this-alt prev-alt))
+ (begin
+ (set! need-accidental #t)
+ (if (and (not (= this-alt 0))
+ (and (< (abs this-alt) (abs prev-alt))
+ (> (* prev-alt this-alt) 0)))
+ (set! need-restore #t))))))
+
+ (cons need-restore need-accidental)))
+
+(define-public ((make-accidental-rule octaveness laziness) context pitch barnum measurepos)
+ "Create an accidental rule that makes its decision based on the octave of
+the note and a laziness value.
+
+@var{octaveness} is either @code{'same-octave} or @code{'any-octave} and
+defines whether the rule should respond to accidental changes in other
+octaves than the current. @code{'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. @code{'any-octave} looks at the last
+active pitch in any octave.
+
+@var{laziness} states over how many bars an accidental should be remembered.
+@code{0}@tie{}is the default -- accidental lasts over 0@tie{}bar lines, that
+is, to the end of current measure. A positive integer means that the
+accidental lasts over that many bar lines. @w{@code{-1}} is `forget
+immediately', that is, only look at key signature. @code{#t} is `forever'."
+
+ (check-pitch-against-signature context pitch barnum laziness octaveness))
projects / lilypond.git / blobdiff