Run grand-replace (issue 3765)

[lilypond.git] / scm / music-functions.scm

diff --git a/scm/music-functions.scm b/scm/music-functions.scm
index 017e7bd3a8dfd819173b12c1fb3a7d87fe141827..05352b0953038c23babc807a6746b9a539453038 100644 (file)
--- a/scm/music-functions.scm
+++ b/scm/music-functions.scm
@@ -1,6 +1,6 @@
 ;;;; This file is part of LilyPond, the GNU music typesetter.
 ;;;;
 ;;;; This file is part of LilyPond, the GNU music typesetter.
 ;;;;

-;;;; Copyright (C) 1998--2012 Jan Nieuwenhuizen <janneke@gnu.org>
+;;;; Copyright (C) 1998--2014 Jan Nieuwenhuizen <janneke@gnu.org>

 ;;;;                 Han-Wen Nienhuys <hanwen@xs4all.nl>
 ;;;;
 ;;;; LilyPond is free software: you can redistribute it and/or modify
 ;;;;                 Han-Wen Nienhuys <hanwen@xs4all.nl>
 ;;;;
 ;;;; LilyPond is free software: you can redistribute it and/or modify


@@ -16,10 +16,11 @@
 ;;;; You should have received a copy of the GNU General Public License
 ;;;; along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
 
 ;;;; You should have received a copy of the GNU General Public License
 ;;;; along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
 

-; for define-safe-public when byte-compiling using Guile V2
+;; for define-safe-public when byte-compiling using Guile V2

 (use-modules (scm safe-utility-defs))
 
 (use-modules (ice-9 optargs))
 (use-modules (scm safe-utility-defs))
 
 (use-modules (ice-9 optargs))

+(use-modules (srfi srfi-11))

 
 ;;; ly:music-property with setter
 ;;; (ly:music-property my-music 'elements)
 
 ;;; ly:music-property with setter
 ;;; (ly:music-property my-music 'elements)


@@ -28,7 +29,7 @@
 ;;;   ==> set the 'elements property and return it
 (define-public ly:music-property
   (make-procedure-with-setter ly:music-property
 ;;;   ==> set the 'elements property and return it
 (define-public ly:music-property
   (make-procedure-with-setter ly:music-property

-                             ly:music-set-property!))
+                              ly:music-set-property!))

 
 (define-safe-public (music-is-of-type? mus type)
   "Does @code{mus} belong to the music class @code{type}?"
 
 (define-safe-public (music-is-of-type? mus type)
   "Does @code{mus} belong to the music class @code{type}?"


@@ -37,23 +38,23 @@
 ;; TODO move this
 (define-public ly:grob-property
   (make-procedure-with-setter ly:grob-property
 ;; TODO move this
 (define-public ly:grob-property
   (make-procedure-with-setter ly:grob-property

-                             ly:grob-set-property!))
+                              ly:grob-set-property!))

 
 (define-public ly:grob-object
   (make-procedure-with-setter ly:grob-object
 
 (define-public ly:grob-object
   (make-procedure-with-setter ly:grob-object

-                             ly:grob-set-object!))
+                              ly:grob-set-object!))

 
 (define-public ly:grob-parent
   (make-procedure-with-setter ly:grob-parent
 
 (define-public ly:grob-parent
   (make-procedure-with-setter ly:grob-parent

-                             ly:grob-set-parent!))
+                              ly:grob-set-parent!))

 
 (define-public ly:prob-property
   (make-procedure-with-setter ly:prob-property
 
 (define-public ly:prob-property
   (make-procedure-with-setter ly:prob-property

-                             ly:prob-set-property!))
+                              ly:prob-set-property!))

 
 (define-public ly:context-property
   (make-procedure-with-setter ly:context-property
 
 (define-public ly:context-property
   (make-procedure-with-setter ly:context-property

-                             ly:context-set-property!))
+                              ly:context-set-property!))

 
 (define-public (music-map function music)
   "Apply @var{function} to @var{music} and all of the music it contains.
 
 (define-public (music-map function music)
   "Apply @var{function} to @var{music} and all of the music it contains.


@@ -61,13 +62,13 @@
 First it recurses over the children, then the function is applied to
 @var{music}."
   (let ((es (ly:music-property music 'elements))
 First it recurses over the children, then the function is applied to
 @var{music}."
   (let ((es (ly:music-property music 'elements))

-       (e (ly:music-property music 'element)))
+        (e (ly:music-property music 'element)))

     (if (pair? es)
     (if (pair? es)

-       (set! (ly:music-property music 'elements)
-             (map (lambda (y) (music-map function y)) es)))
+        (set! (ly:music-property music 'elements)
+              (map (lambda (y) (music-map function y)) es)))

     (if (ly:music? e)
     (if (ly:music? e)

-       (set! (ly:music-property music 'element)
-             (music-map function  e)))
+        (set! (ly:music-property music 'element)
+              (music-map function  e)))

     (function music)))
 
 (define-public (music-filter pred? music)
     (function music)))
 
 (define-public (music-filter pred? music)


@@ -76,31 +77,31 @@ First it recurses over the children, then the function is applied to
   (define (inner-music-filter pred? music)
     "Recursive function."
     (let* ((es (ly:music-property music 'elements))
   (define (inner-music-filter pred? music)
     "Recursive function."
     (let* ((es (ly:music-property music 'elements))

-          (e (ly:music-property music 'element))
-          (as (ly:music-property music 'articulations))
-          (filtered-as (filter ly:music? (map (lambda (y) (inner-music-filter pred? y)) as)))
-          (filtered-e (if (ly:music? e)
-                          (inner-music-filter pred? e)
-                          e))
-          (filtered-es (filter ly:music? (map (lambda (y) (inner-music-filter pred? y)) es))))
+           (e (ly:music-property music 'element))
+           (as (ly:music-property music 'articulations))
+           (filtered-as (filter ly:music? (map (lambda (y) (inner-music-filter pred? y)) as)))
+           (filtered-e (if (ly:music? e)
+                           (inner-music-filter pred? e)
+                           e))
+           (filtered-es (filter ly:music? (map (lambda (y) (inner-music-filter pred? y)) es))))

       (if (not (null? e))
       (if (not (null? e))

-         (set! (ly:music-property music 'element) filtered-e))
+          (set! (ly:music-property music 'element) filtered-e))

       (if (not (null? es))
       (if (not (null? es))

-         (set! (ly:music-property music 'elements) filtered-es))
+          (set! (ly:music-property music 'elements) filtered-es))

       (if (not (null? as))
       (if (not (null? as))

-         (set! (ly:music-property music 'articulations) filtered-as))
+          (set! (ly:music-property music 'articulations) filtered-as))

       ;; if filtering emptied the expression, we remove it completely.
       (if (or (not (pred? music))
       ;; if filtering emptied the expression, we remove it completely.
       (if (or (not (pred? music))

-             (and (eq? filtered-es '()) (not (ly:music? e))
-                  (or (not (eq? es '()))
-                      (ly:music? e))))
-         (set! music '()))
+              (and (eq? filtered-es '()) (not (ly:music? e))
+                   (or (not (eq? es '()))
+                       (ly:music? e))))
+          (set! music '()))

       music))
 
   (set! music (inner-music-filter pred? music))
   (if (ly:music? music)
       music
       music))
 
   (set! music (inner-music-filter pred? music))
   (if (ly:music? music)
       music

-      (make-music 'Music)))      ;must return music.
+      (make-music 'Music)))       ;must return music.

 
 (define*-public (display-music music #:optional (port (current-output-port)))
   "Display music, not done with @code{music-map} for clarity of
 
 (define*-public (display-music music #:optional (port (current-output-port)))
   "Display music, not done with @code{music-map} for clarity of


@@ -108,16 +109,16 @@ presentation."
   (display music port)
   (display ": { " port)
   (let ((es (ly:music-property music 'elements))
   (display music port)
   (display ": { " port)
   (let ((es (ly:music-property music 'elements))

-       (e (ly:music-property music 'element)))
+        (e (ly:music-property music 'element)))

     (display (ly:music-mutable-properties music) port)
     (if (pair? es)
     (display (ly:music-mutable-properties music) port)
     (if (pair? es)

-       (begin (display "\nElements: {\n" port)
-              (for-each (lambda (m) (display-music m port)) es)
-              (display "}\n" port)))
+        (begin (display "\nElements: {\n" port)
+               (for-each (lambda (m) (display-music m port)) es)
+               (display "}\n" port)))

     (if (ly:music? e)
     (if (ly:music? e)

-       (begin
-         (display "\nChild:" port)
-         (display-music e port))))
+        (begin
+          (display "\nChild:" port)
+          (display-music e port))))

   (display " }\n" port)
   music)
 
   (display " }\n" port)
   music)
 


@@ -134,20 +135,20 @@ For instance,
     "Return a keyword, eg. `#:bold', from the `proc' function, eg. #<procedure bold-markup (layout props arg)>"
     (let ((cmd-markup (symbol->string (procedure-name proc))))
       (symbol->keyword (string->symbol (substring cmd-markup 0 (- (string-length cmd-markup)
     "Return a keyword, eg. `#:bold', from the `proc' function, eg. #<procedure bold-markup (layout props arg)>"
     (let ((cmd-markup (symbol->string (procedure-name proc))))
       (symbol->keyword (string->symbol (substring cmd-markup 0 (- (string-length cmd-markup)

-                                                                 (string-length "-markup")))))))
+                                                                  (string-length "-markup")))))))

   (define (transform-arg arg)
     (cond ((and (pair? arg) (markup? (car arg))) ;; a markup list
   (define (transform-arg arg)
     (cond ((and (pair? arg) (markup? (car arg))) ;; a markup list

-          (apply append (map inner-markup->make-markup arg)))
-         ((and (not (string? arg)) (markup? arg)) ;; a markup
-          (inner-markup->make-markup arg))
-         (else                                  ;; scheme arg
-          (music->make-music arg))))
+           (append-map inner-markup->make-markup arg))
+          ((and (not (string? arg)) (markup? arg)) ;; a markup
+           (inner-markup->make-markup arg))
+          (else                                  ;; scheme arg
+           (music->make-music arg))))

   (define (inner-markup->make-markup mrkup)
     (if (string? mrkup)
   (define (inner-markup->make-markup mrkup)
     (if (string? mrkup)

-       `(#:simple ,mrkup)
-       (let ((cmd (proc->command-keyword (car mrkup)))
-             (args (map transform-arg (cdr mrkup))))
-         `(,cmd ,@args))))
+        `(#:simple ,mrkup)
+        (let ((cmd (proc->command-keyword (car mrkup)))
+              (args (map transform-arg (cdr mrkup))))
+          `(,cmd ,@args))))

   ;; body:
   (if (string? markup-expression)
       markup-expression
   ;; body:
   (if (string? markup-expression)
       markup-expression


@@ -158,52 +159,52 @@ For instance,
 equivalent to @var{obj}, that is, for a music expression, a
 @code{(make-music ...)} form."
   (cond (;; markup expression
 equivalent to @var{obj}, that is, for a music expression, a
 @code{(make-music ...)} form."
   (cond (;; markup expression

-        (markup? obj)
-        (markup-expression->make-markup obj))
-       (;; music expression
-        (ly:music? obj)
-        `(make-music
-          ',(ly:music-property obj 'name)
-          ,@(apply append (map (lambda (prop)
-                                  `(',(car prop)
-                                   ,(music->make-music (cdr prop))))
-                                (remove (lambda (prop)
-                                          (eqv? (car prop) 'origin))
-                                        (ly:music-mutable-properties obj))))))
-       (;; moment
-        (ly:moment? obj)
-        `(ly:make-moment ,(ly:moment-main-numerator obj)
-                         ,(ly:moment-main-denominator obj)
-                         ,(ly:moment-grace-numerator obj)
-                         ,(ly:moment-grace-denominator obj)))
-       (;; note duration
-        (ly:duration? obj)
-        `(ly:make-duration ,(ly:duration-log obj)
-                           ,(ly:duration-dot-count obj)
-                           ,(ly:duration-scale obj)))
-       (;; note pitch
-        (ly:pitch? obj)
-        `(ly:make-pitch ,(ly:pitch-octave obj)
-                        ,(ly:pitch-notename obj)
-                        ,(ly:pitch-alteration obj)))
-       (;; scheme procedure
-        (procedure? obj)
-        (or (procedure-name obj) obj))
-       (;; a symbol (avoid having an unquoted symbol)
-        (symbol? obj)
-        `',obj)
-       (;; an empty list (avoid having an unquoted empty list)
-        (null? obj)
-        `'())
-       (;; a proper list
-        (list? obj)
-        `(list ,@(map music->make-music obj)))
-       (;; a pair
-        (pair? obj)
-        `(cons ,(music->make-music (car obj))
-               ,(music->make-music (cdr obj))))
-       (else
-        obj)))
+         (markup? obj)
+         (markup-expression->make-markup obj))
+        (;; music expression
+         (ly:music? obj)
+         `(make-music
+           ',(ly:music-property obj 'name)
+           ,@(append-map (lambda (prop)
+                           `(',(car prop)
+                             ,(music->make-music (cdr prop))))
+                         (remove (lambda (prop)
+                                   (eqv? (car prop) 'origin))
+                                 (ly:music-mutable-properties obj)))))
+        (;; moment
+         (ly:moment? obj)
+         `(ly:make-moment ,(ly:moment-main-numerator obj)
+                          ,(ly:moment-main-denominator obj)
+                          ,(ly:moment-grace-numerator obj)
+                          ,(ly:moment-grace-denominator obj)))
+        (;; note duration
+         (ly:duration? obj)
+         `(ly:make-duration ,(ly:duration-log obj)
+                            ,(ly:duration-dot-count obj)
+                            ,(ly:duration-scale obj)))
+        (;; note pitch
+         (ly:pitch? obj)
+         `(ly:make-pitch ,(ly:pitch-octave obj)
+                         ,(ly:pitch-notename obj)
+                         ,(ly:pitch-alteration obj)))
+        (;; scheme procedure
+         (procedure? obj)
+         (or (procedure-name obj) obj))
+        (;; a symbol (avoid having an unquoted symbol)
+         (symbol? obj)
+         `',obj)
+        (;; an empty list (avoid having an unquoted empty list)
+         (null? obj)
+         `'())
+        (;; a proper list
+         (list? obj)
+         `(list ,@(map music->make-music obj)))
+        (;; a pair
+         (pair? obj)
+         `(cons ,(music->make-music (car obj))
+                ,(music->make-music (cdr obj))))
+        (else
+         obj)))

 
 (use-modules (ice-9 pretty-print))
 (define*-public (display-scheme-music obj #:optional (port (current-output-port)))
 
 (use-modules (ice-9 pretty-print))
 (define*-public (display-scheme-music obj #:optional (port (current-output-port)))


@@ -219,14 +220,14 @@ which often can be read back in order to generate an equivalent expression."
              (scm display-lily))
 
 (define*-public (display-lily-music expr parser #:optional (port (current-output-port))
              (scm display-lily))
 
 (define*-public (display-lily-music expr parser #:optional (port (current-output-port))

-                                   #:key force-duration)
+                                    #:key force-duration)

   "Display the music expression using LilyPond syntax"
   (memoize-clef-names supported-clefs)
   (parameterize ((*indent* 0)
   "Display the music expression using LilyPond syntax"
   (memoize-clef-names supported-clefs)
   (parameterize ((*indent* 0)

-                (*previous-duration* (ly:make-duration 2))
-                (*force-duration* force-duration))
-    (display (music->lily-string expr parser) port)
-    (newline port)))
+                 (*previous-duration* (ly:make-duration 2))
+                 (*force-duration* force-duration))
+                (display (music->lily-string expr parser) port)
+                (newline port)))

 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 


@@ -236,17 +237,17 @@ which often can be read back in order to generate an equivalent expression."
 The number of dots in the shifted music may not be less than zero."
   (let ((d (ly:music-property music 'duration)))
     (if (ly:duration? d)
 The number of dots in the shifted music may not be less than zero."
   (let ((d (ly:music-property music 'duration)))
     (if (ly:duration? d)

-       (let* ((cp (ly:duration-scale d))
-              (nd (ly:make-duration
+        (let* ((cp (ly:duration-scale d))
+               (nd (ly:make-duration

                     (+ shift (ly:duration-log d))
                     (max 0 (+ dot (ly:duration-dot-count d)))
                     (+ shift (ly:duration-log d))
                     (max 0 (+ dot (ly:duration-dot-count d)))

-                   cp)))
-         (set! (ly:music-property music 'duration) nd)))
+                    cp)))
+          (set! (ly:music-property music 'duration) nd)))

     music))
 
 (define-public (shift-duration-log music shift dot)
   (music-map (lambda (x) (shift-one-duration-log x shift dot))
     music))
 
 (define-public (shift-duration-log music shift dot)
   (music-map (lambda (x) (shift-one-duration-log x shift dot))

-            music))
+             music))

 
 (define-public (make-repeat name times main alts)
   "Create a repeat music expression, with all properties initialized
 
 (define-public (make-repeat name times main alts)
   "Create a repeat music expression, with all properties initialized


@@ -257,55 +258,55 @@ through MUSIC."
     ;; NoteEvent or a non-expanded chord-repetition
     ;; We just take anything that actually sports an announced duration.
     (if (ly:duration? (ly:music-property music 'duration))
     ;; NoteEvent or a non-expanded chord-repetition
     ;; We just take anything that actually sports an announced duration.
     (if (ly:duration? (ly:music-property music 'duration))

-       (ly:music-property music 'duration)
-       (let loop ((elts (if (ly:music? (ly:music-property music 'element))
-                            (list (ly:music-property music 'element))
-                            (ly:music-property music 'elements))))
-         (and (pair? elts)
-              (let ((dur (first-note-duration (car elts))))
-                (if (ly:duration? dur)
-                    dur
-                    (loop (cdr elts))))))))
+        (ly:music-property music 'duration)
+        (let loop ((elts (if (ly:music? (ly:music-property music 'element))
+                             (list (ly:music-property music 'element))
+                             (ly:music-property music 'elements))))
+          (and (pair? elts)
+               (let ((dur (first-note-duration (car elts))))
+                 (if (ly:duration? dur)
+                     dur
+                     (loop (cdr elts))))))))

 
   (let ((talts (if (< times (length alts))
 
   (let ((talts (if (< times (length alts))

-                  (begin
-                    (ly:warning (_ "More alternatives than repeats.  Junking excess alternatives"))
-                    (take alts times))
-                  alts))
-       (r (make-repeated-music name)))
+                   (begin
+                     (ly:warning (_ "More alternatives than repeats.  Junking excess alternatives"))
+                     (take alts times))
+                   alts))
+        (r (make-repeated-music name)))

     (set! (ly:music-property r 'element) main)
     (set! (ly:music-property r 'repeat-count) (max times 1))
     (set! (ly:music-property r 'elements) talts)
     (if (and (equal? name "tremolo")
     (set! (ly:music-property r 'element) main)
     (set! (ly:music-property r 'repeat-count) (max times 1))
     (set! (ly:music-property r 'elements) talts)
     (if (and (equal? name "tremolo")

-            (pair? (extract-named-music main '(EventChord NoteEvent))))
-       ;; This works for single-note and multi-note tremolos!
-       (let* ((children (if (music-is-of-type? main 'sequential-music)
-                            ;; \repeat tremolo n { ... }
-                            (length (extract-named-music main '(EventChord
-                                                                NoteEvent)))
-                            ;; \repeat tremolo n c4
-                            1))
-              ;; # of dots is equal to the 1 in bitwise representation (minus 1)!
-              (dots (1- (logcount (* times children))))
-              ;; The remaining missing multiplicator to scale the notes by
-              ;; times * children
-              (mult (/ (* times children (ash 1 dots)) (1- (ash 2 dots))))
-              (shift (- (ly:intlog2 (floor mult))))
-              (note-duration (first-note-duration r))
-              (duration-log (if (ly:duration? note-duration)
-                                (ly:duration-log note-duration)
-                                1))
-              (tremolo-type (ash 1 duration-log)))
-         (set! (ly:music-property r 'tremolo-type) tremolo-type)
-         (if (not (and (integer? mult) (= (logcount mult) 1)))
-             (ly:music-warning
-              main
-              (ly:format (_ "invalid tremolo repeat count: ~a") times)))
-         ;; Adjust the time of the notes
-         (ly:music-compress r (ly:make-moment 1 children))
-         ;; Adjust the displayed note durations
-         (shift-duration-log r shift dots))
-       r)))
+             (pair? (extract-named-music main '(EventChord NoteEvent))))
+        ;; This works for single-note and multi-note tremolos!
+        (let* ((children (if (music-is-of-type? main 'sequential-music)
+                             ;; \repeat tremolo n { ... }
+                             (length (extract-named-music main '(EventChord
+                                                                 NoteEvent)))
+                             ;; \repeat tremolo n c4
+                             1))
+               ;; # of dots is equal to the 1 in bitwise representation (minus 1)!
+               (dots (1- (logcount (* times children))))
+               ;; The remaining missing multiplicator to scale the notes by
+               ;; times * children
+               (mult (/ (* times children (ash 1 dots)) (1- (ash 2 dots))))
+               (shift (- (ly:intlog2 (floor mult))))
+               (note-duration (first-note-duration r))
+               (duration-log (if (ly:duration? note-duration)
+                                 (ly:duration-log note-duration)
+                                 1))
+               (tremolo-type (ash 1 duration-log)))
+          (set! (ly:music-property r 'tremolo-type) tremolo-type)
+          (if (not (and (integer? mult) (= (logcount mult) 1)))
+              (ly:music-warning
+               main
+               (ly:format (_ "invalid tremolo repeat count: ~a") times)))
+          ;; Adjust the time of the notes
+          (ly:music-compress r (ly:make-moment 1 children))
+          ;; Adjust the displayed note durations
+          (shift-duration-log r shift dots))
+        r)))

 
 (define (calc-repeat-slash-count music)
   "Given the child-list @var{music} in @code{PercentRepeatMusic},
 
 (define (calc-repeat-slash-count music)
   "Given the child-list @var{music} in @code{PercentRepeatMusic},


@@ -313,13 +314,13 @@ calculate the number of slashes based on the durations.  Returns @code{0}
 if durations in @var{music} vary, allowing slash beats and double-percent
 beats to be distinguished."
   (let* ((durs (map duration-of-note
 if durations in @var{music} vary, allowing slash beats and double-percent
 beats to be distinguished."
   (let* ((durs (map duration-of-note

-                   (extract-named-music music '(EventChord NoteEvent
-                                                RestEvent SkipEvent))))
-        (first-dur (car durs)))
+                    (extract-named-music music '(EventChord NoteEvent
+                                                            RestEvent SkipEvent))))
+         (first-dur (car durs)))

 
     (if (every (lambda (d) (equal? d first-dur)) durs)
 
     (if (every (lambda (d) (equal? d first-dur)) durs)

-       (max (- (ly:duration-log first-dur) 2) 1)
-       0)))
+        (max (- (ly:duration-log first-dur) 2) 1)
+        0)))

 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; clusters.
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; clusters.


@@ -328,8 +329,8 @@ beats to be distinguished."
   "Replace @code{NoteEvents} by @code{ClusterNoteEvents}."
   (if (eq? (ly:music-property music 'name) 'NoteEvent)
       (make-music 'ClusterNoteEvent
   "Replace @code{NoteEvents} by @code{ClusterNoteEvents}."
   (if (eq? (ly:music-property music 'name) 'NoteEvent)
       (make-music 'ClusterNoteEvent

-                 'pitch (ly:music-property music 'pitch)
-                 'duration (ly:music-property music 'duration))
+                  'pitch (ly:music-property music 'pitch)
+                  'duration (ly:music-property music 'duration))

       music))
 
 (define-public (notes-to-clusters music)
       music))
 
 (define-public (notes-to-clusters music)


@@ -342,71 +343,167 @@ beats to be distinguished."
   "Replace all repeats with unfolded repeats."
 
   (let ((es (ly:music-property music 'elements))
   "Replace all repeats with unfolded repeats."
 
   (let ((es (ly:music-property music 'elements))

-       (e (ly:music-property music 'element)))
+        (e (ly:music-property music 'element)))

 
     (if (music-is-of-type? music 'repeated-music)
 
     (if (music-is-of-type? music 'repeated-music)

-       (let* ((props (ly:music-mutable-properties music))
-              (old-name (ly:music-property music 'name))
-              (flattened (flatten-alist props)))
-         (set! music (apply make-music (cons 'UnfoldedRepeatedMusic
-                                             flattened)))
-
-         (if (and (equal? old-name 'TremoloRepeatedMusic)
-                  (pair? (extract-named-music e '(EventChord NoteEvent))))
-             ;; This works for single-note and multi-note tremolos!
-             (let* ((children (if (music-is-of-type? e 'sequential-music)
-                                  ;; \repeat tremolo n { ... }
-                                  (length (extract-named-music e '(EventChord
-                                                                      NoteEvent)))
-                                  ;; \repeat tremolo n c4
-                                  1))
-                    (times (ly:music-property music 'repeat-count))
-
-                    ;; # of dots is equal to the 1 in bitwise representation (minus 1)!
-                    (dots (1- (logcount (* times children))))
-                    ;; The remaining missing multiplicator to scale the notes by
-                    ;; times * children
-                    (mult (/ (* times children (ash 1 dots)) (1- (ash 2 dots))))
-                    (shift (- (ly:intlog2 (floor mult)))))
-
-               ;; Adjust the time of the notes
-               (ly:music-compress music (ly:make-moment children 1))
-               ;; Adjust the displayed note durations
-               (shift-duration-log music (- shift) (- dots))))))
+        (let* ((props (ly:music-mutable-properties music))
+               (old-name (ly:music-property music 'name))
+               (flattened (flatten-alist props)))
+          (set! music (apply make-music (cons 'UnfoldedRepeatedMusic
+                                              flattened)))
+
+          (if (and (equal? old-name 'TremoloRepeatedMusic)
+                   (pair? (extract-named-music e '(EventChord NoteEvent))))
+              ;; This works for single-note and multi-note tremolos!
+              (let* ((children (if (music-is-of-type? e 'sequential-music)
+                                   ;; \repeat tremolo n { ... }
+                                   (length (extract-named-music e '(EventChord
+                                                                    NoteEvent)))
+                                   ;; \repeat tremolo n c4
+                                   1))
+                     (times (ly:music-property music 'repeat-count))
+
+                     ;; # of dots is equal to the 1 in bitwise representation (minus 1)!
+                     (dots (1- (logcount (* times children))))
+                     ;; The remaining missing multiplicator to scale the notes by
+                     ;; times * children
+                     (mult (/ (* times children (ash 1 dots)) (1- (ash 2 dots))))
+                     (shift (- (ly:intlog2 (floor mult)))))
+
+                ;; Adjust the time of the notes
+                (ly:music-compress music (ly:make-moment children 1))
+                ;; Adjust the displayed note durations
+                (shift-duration-log music (- shift) (- dots))))))

 
     (if (pair? es)
 
     (if (pair? es)

-       (set! (ly:music-property music 'elements)
-             (map unfold-repeats es)))
+        (set! (ly:music-property music 'elements)
+              (map unfold-repeats es)))

     (if (ly:music? e)
     (if (ly:music? e)

-       (set! (ly:music-property music 'element)
-             (unfold-repeats e)))
+        (set! (ly:music-property music 'element)
+              (unfold-repeats e)))

     music))
 
     music))
 

+(define-public (unfold-repeats-fully music)
+  "Unfolds repeats and expands the resulting @code{unfolded-repeated-music}."
+  (map-some-music
+   (lambda (m)
+     (and (music-is-of-type? m 'unfolded-repeated-music)
+          (make-sequential-music
+           (ly:music-deep-copy
+            (let ((n (ly:music-property m 'repeat-count))
+                  (alts (ly:music-property m 'elements))
+                  (body (ly:music-property m 'element)))
+              (cond ((<= n 0) '())
+                    ((null? alts) (make-list n body))
+                    (else
+                     (concatenate
+                      (zip (make-list n body)
+                           (append! (make-list (max 0 (- n (length alts)))
+                                               (car alts))
+                                    alts))))))))))
+   (unfold-repeats music)))
+

 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; property setting music objs.
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; property setting music objs.
 

+(define-safe-public (check-grob-path path #:optional parser location
+                                     #:key
+                                     (start 0)
+                                     default
+                                     (min 1)
+                                     max)
+  "Check a grob path specification @var{path}, a symbol list (or a
+single symbol), for validity and possibly complete it.  Returns the
+completed specification, or @code{#f} if invalid.  If optional
+@var{parser} is given, a syntax error is raised in that case,
+optionally using @var{location}.  If an optional keyword argument
+@code{#:start @var{start}} is given, the parsing starts at the given
+index in the sequence @samp{Context.Grob.property.sub-property...},
+with the default of @samp{0} implying the full path.
+
+If there is no valid first element of @var{path} fitting at the given
+path location, an optionally given @code{#:default @var{default}} is
+used as the respective element instead without checking it for
+validity at this position.
+
+The resulting path after possibly prepending @var{default} can be
+constrained in length by optional arguments @code{#:min @var{min}} and
+@code{#:max @var{max}}, defaulting to @samp{1} and unlimited,
+respectively."
+  (let ((path (if (symbol? path) (list path) path)))
+    ;; A Guile 1.x bug specific to optargs precludes moving the
+    ;; defines out of the let
+    (define (unspecial? s)
+      (not (or (object-property s 'is-grob?)
+               (object-property s 'backend-type?))))
+    (define (grob? s)
+      (object-property s 'is-grob?))
+    (define (property? s)
+      (object-property s 'backend-type?))
+    (define (check c p) (c p))
+
+    (let* ((checkers
+            (and (< start 3)
+                 (drop (list unspecial? grob? property?) start)))
+           (res
+            (cond
+             ((null? path)
+              ;; tricky.  Should we make use of the default when the
+              ;; list is empty?  In most cases, this question should be
+              ;; academical as an empty list can only be generated by
+              ;; Scheme and is likely an error.  We consider this a case
+              ;; of "no valid first element, and default given".
+              ;; Usually, invalid use cases should be caught later using
+              ;; the #:min argument, and if the user explicitly does not
+              ;; catch this, we just follow through.
+              (if default (list default) '()))
+             ((not checkers)
+              ;; no checkers, so we have a valid first element and just
+              ;; take the path as-is.
+              path)
+             (default
+               (if ((car checkers) (car path))
+                   (and (every check (cdr checkers) (cdr path))
+                        path)
+                   (and (every check (cdr checkers) path)
+                        (cons default path))))
+             (else
+              (and (every check checkers path)
+                   path)))))
+      (if (and res
+               (if max (<= min (length res) max)
+                   (<= min (length res))))
+          res
+          (begin
+            (if parser
+                (ly:parser-error parser
+                                 (format #f (_ "bad grob property path ~a")
+                                         path)
+                                 location))
+            #f)))))
+

 (define-public (make-grob-property-set grob gprop val)
   "Make a @code{Music} expression that sets @var{gprop} to @var{val} in
 @var{grob}.  Does a pop first, i.e., this is not an override."
   (make-music 'OverrideProperty
 (define-public (make-grob-property-set grob gprop val)
   "Make a @code{Music} expression that sets @var{gprop} to @var{val} in
 @var{grob}.  Does a pop first, i.e., this is not an override."
   (make-music 'OverrideProperty

-             'symbol grob
-             'grob-property gprop
-             'grob-value val
-             'pop-first #t))
+              'symbol grob
+              'grob-property gprop
+              'grob-value val
+              'pop-first #t))

 
 (define-public (make-grob-property-override grob gprop val)
   "Make a @code{Music} expression that overrides @var{gprop} to @var{val}
 in @var{grob}."
   (make-music 'OverrideProperty
 
 (define-public (make-grob-property-override grob gprop val)
   "Make a @code{Music} expression that overrides @var{gprop} to @var{val}
 in @var{grob}."
   (make-music 'OverrideProperty

-             'symbol grob
-             'grob-property gprop
-             'grob-value val))
+              'symbol grob
+              'grob-property gprop
+              'grob-value val))

 
 (define-public (make-grob-property-revert grob gprop)
   "Revert the grob property @var{gprop} for @var{grob}."
   (make-music 'RevertProperty
 
 (define-public (make-grob-property-revert grob gprop)
   "Revert the grob property @var{gprop} for @var{grob}."
   (make-music 'RevertProperty

-             'symbol grob
-             'grob-property gprop))
+              'symbol grob
+              'grob-property gprop))

 
 (define direction-polyphonic-grobs
   '(AccidentalSuggestion
 
 (define direction-polyphonic-grobs
   '(AccidentalSuggestion


@@ -415,6 +512,7 @@ in @var{grob}."
     Fingering
     LaissezVibrerTie
     LigatureBracket
     Fingering
     LaissezVibrerTie
     LigatureBracket

+    MultiMeasureRest

     PhrasingSlur
     RepeatTie
     Rest
     PhrasingSlur
     RepeatTie
     Rest


@@ -426,77 +524,64 @@ in @var{grob}."
     TupletBracket
     TrillSpanner))
 
     TupletBracket
     TrillSpanner))
 

+(define general-grace-settings
+  `((Voice Stem font-size -3)
+    (Voice Flag font-size -3)
+    (Voice NoteHead font-size -3)
+    (Voice TabNoteHead font-size -4)
+    (Voice Dots font-size -3)
+    (Voice Stem length-fraction 0.8)
+    (Voice Stem no-stem-extend #t)
+    (Voice Beam beam-thickness 0.384)
+    (Voice Beam length-fraction 0.8)
+    (Voice Accidental font-size -4)
+    (Voice AccidentalCautionary font-size -4)
+    (Voice Script font-size -3)
+    (Voice Fingering font-size -8)
+    (Voice StringNumber font-size -8)))
+
+(define-public score-grace-settings
+  (append
+    `((Voice Stem direction ,UP)
+      (Voice Slur direction ,DOWN))
+    general-grace-settings))
+

 (define-safe-public (make-voice-props-set n)
   (make-sequential-music
    (append
     (map (lambda (x) (make-grob-property-set x 'direction
 (define-safe-public (make-voice-props-set n)
   (make-sequential-music
    (append
     (map (lambda (x) (make-grob-property-set x 'direction

-                                                 (if (odd? n) -1 1)))
-        direction-polyphonic-grobs)
+                                             (if (odd? n) -1 1)))
+         direction-polyphonic-grobs)

     (list
     (list

-     (make-property-set 'graceSettings
-                       ;; TODO: take this from voicedGraceSettings or similar.
-                       '((Voice Stem font-size -3)
-                         (Voice Flag font-size -3)
-                         (Voice NoteHead font-size -3)
-                         (Voice TabNoteHead font-size -4)
-                         (Voice Dots font-size -3)
-                         (Voice Stem length-fraction 0.8)
-                         (Voice Stem no-stem-extend #t)
-                         (Voice Beam beam-thickness 0.384)
-                         (Voice Beam length-fraction 0.8)
-                         (Voice Accidental font-size -4)
-                         (Voice AccidentalCautionary font-size -4)
-                         (Voice Script font-size -3)
-                         (Voice Fingering font-size -8)
-                         (Voice StringNumber font-size -8)))
-
-     (make-grob-property-set 'NoteColumn 'horizontal-shift (quotient n 2))
-     (make-grob-property-set 'MultiMeasureRest 'staff-position (if (odd? n) -4 4))))))
+     (make-property-set 'graceSettings general-grace-settings)
+     (make-grob-property-set 'NoteColumn 'horizontal-shift (quotient n 2))))))

 
 (define-safe-public (make-voice-props-override n)
   (make-sequential-music
    (append
     (map (lambda (x) (make-grob-property-override x 'direction
 
 (define-safe-public (make-voice-props-override n)
   (make-sequential-music
    (append
     (map (lambda (x) (make-grob-property-override x 'direction

-                                                 (if (odd? n) -1 1)))
-        direction-polyphonic-grobs)
+                                                  (if (odd? n) -1 1)))
+         direction-polyphonic-grobs)

     (list
     (list

-     (make-property-set 'graceSettings
-                       ;; TODO: take this from voicedGraceSettings or similar.
-                       '((Voice Stem font-size -3)
-                         (Voice Flag font-size -3)
-                         (Voice NoteHead font-size -3)
-                         (Voice TabNoteHead font-size -4)
-                         (Voice Dots font-size -3)
-                         (Voice Stem length-fraction 0.8)
-                         (Voice Stem no-stem-extend #t)
-                         (Voice Beam beam-thickness 0.384)
-                         (Voice Beam length-fraction 0.8)
-                         (Voice Accidental font-size -4)
-                         (Voice AccidentalCautionary font-size -4)
-                         (Voice Script font-size -3)
-                         (Voice Fingering font-size -8)
-                         (Voice StringNumber font-size -8)))
-
-     (make-grob-property-override 'NoteColumn 'horizontal-shift (quotient n 2))
-     (make-grob-property-override 'MultiMeasureRest 'staff-position (if (odd? n) -4 4))))))
+     (make-property-set 'graceSettings general-grace-settings)
+     (make-grob-property-override 'NoteColumn 'horizontal-shift (quotient n 2))))))

 
 (define-safe-public (make-voice-props-revert)
   (make-sequential-music
    (append
     (map (lambda (x) (make-grob-property-revert x 'direction))
 
 (define-safe-public (make-voice-props-revert)
   (make-sequential-music
    (append
     (map (lambda (x) (make-grob-property-revert x 'direction))

-        direction-polyphonic-grobs)
+         direction-polyphonic-grobs)

     (list (make-property-unset 'graceSettings)
     (list (make-property-unset 'graceSettings)

-         (make-grob-property-revert 'NoteColumn 'horizontal-shift)
-         (make-grob-property-revert 'MultiMeasureRest 'staff-position)))))
+          (make-grob-property-revert 'NoteColumn 'horizontal-shift)))))

 
 
 (define-safe-public (context-spec-music m context #:optional id)
   "Add \\context CONTEXT = ID to M."
   (let ((cm (make-music 'ContextSpeccedMusic
 
 
 (define-safe-public (context-spec-music m context #:optional id)
   "Add \\context CONTEXT = ID to M."
   (let ((cm (make-music 'ContextSpeccedMusic

-                       'element m
-                       'context-type context)))
+                        'element m
+                        'context-type context)))

     (if (string? id)
     (if (string? id)

-       (set! (ly:music-property cm 'context-id) id))
+        (set! (ly:music-property cm 'context-id) id))

     cm))
 
 (define-public (descend-to-context m context)
     cm))
 
 (define-public (descend-to-context m context)


@@ -507,82 +592,83 @@ in @var{grob}."
 
 (define-public (make-non-relative-music mus)
   (make-music 'UnrelativableMusic
 
 (define-public (make-non-relative-music mus)
   (make-music 'UnrelativableMusic

-             'element mus))
+              'element mus))

 
 (define-public (make-apply-context func)
   (make-music 'ApplyContext
 
 (define-public (make-apply-context func)
   (make-music 'ApplyContext

-             'procedure func))
+              'procedure func))

 
 (define-public (make-sequential-music elts)
   (make-music 'SequentialMusic
 
 (define-public (make-sequential-music elts)
   (make-music 'SequentialMusic

-             'elements elts))
+              'elements elts))

 
 (define-public (make-simultaneous-music elts)
   (make-music 'SimultaneousMusic
 
 (define-public (make-simultaneous-music elts)
   (make-music 'SimultaneousMusic

-             'elements elts))
+              'elements elts))

 
 (define-safe-public (make-event-chord elts)
   (make-music 'EventChord
 
 (define-safe-public (make-event-chord elts)
   (make-music 'EventChord

-             'elements elts))
+              'elements elts))

 
 (define-public (make-skip-music dur)
   (make-music 'SkipMusic
 
 (define-public (make-skip-music dur)
   (make-music 'SkipMusic

-             'duration dur))
+              'duration dur))

 
 (define-public (make-grace-music music)
   (make-music 'GraceMusic
 
 (define-public (make-grace-music music)
   (make-music 'GraceMusic

-             'element music))
+              'element music))

 
 ;;;;;;;;;;;;;;;;
 
 ;; mmrest
 (define-public (make-multi-measure-rest duration location)
   (make-music 'MultiMeasureRestMusic
 
 ;;;;;;;;;;;;;;;;
 
 ;; mmrest
 (define-public (make-multi-measure-rest duration location)
   (make-music 'MultiMeasureRestMusic

-             'origin location
-             'duration duration))
+              'origin location
+              'duration duration))

 
 (define-public (make-property-set sym val)
   (make-music 'PropertySet
 
 (define-public (make-property-set sym val)
   (make-music 'PropertySet

-             'symbol sym
-             'value val))
+              'symbol sym
+              'value val))

 
 (define-public (make-property-unset sym)
   (make-music 'PropertyUnset
 
 (define-public (make-property-unset sym)
   (make-music 'PropertyUnset

-             'symbol sym))
+              'symbol sym))

 
 

-(define-safe-public (make-articulation name)
-  (make-music 'ArticulationEvent
-             'articulation-type name))
+(define-safe-public (make-articulation name . properties)
+  (apply make-music 'ArticulationEvent
+         'articulation-type name
+         properties))

 
 (define-public (make-lyric-event string duration)
   (make-music 'LyricEvent
 
 (define-public (make-lyric-event string duration)
   (make-music 'LyricEvent

-             'duration duration
-             'text string))
+              'duration duration
+              'text string))

 
 (define-safe-public (make-span-event type span-dir)
   (make-music type
 
 (define-safe-public (make-span-event type span-dir)
   (make-music type

-             'span-direction span-dir))
+              'span-direction span-dir))

 
 (define-public (override-head-style heads style)
   "Override style for @var{heads} to @var{style}."
   (make-sequential-music
 
 (define-public (override-head-style heads style)
   "Override style for @var{heads} to @var{style}."
   (make-sequential-music

-    (if (pair? heads)
-        (map (lambda (h)
+   (if (pair? heads)
+       (map (lambda (h)

               (make-grob-property-override h 'style style))
               (make-grob-property-override h 'style style))

-         heads)
-        (list (make-grob-property-override heads 'style style)))))
+            heads)
+       (list (make-grob-property-override heads 'style style)))))

 
 (define-public (revert-head-style heads)
   "Revert style for @var{heads}."
   (make-sequential-music
 
 (define-public (revert-head-style heads)
   "Revert style for @var{heads}."
   (make-sequential-music

-    (if (pair? heads)
-        (map (lambda (h)
+   (if (pair? heads)
+       (map (lambda (h)

               (make-grob-property-revert h 'style))
               (make-grob-property-revert h 'style))

-         heads)
-        (list (make-grob-property-revert heads 'style)))))
+            heads)
+       (list (make-grob-property-revert heads 'style)))))

 
 (define-public (style-note-heads heads style music)
 
 (define-public (style-note-heads heads style music)

- "Set @var{style} for all @var{heads} in @var{music}.  Works both
+  "Set @var{style} for all @var{heads} in @var{music}.  Works both

 inside of and outside of chord construct."
   ;; are we inside a <...>?
   (if (eq? (ly:music-property music 'name) 'NoteEvent)
 inside of and outside of chord construct."
   ;; are we inside a <...>?
   (if (eq? (ly:music-property music 'name) 'NoteEvent)


@@ -593,17 +679,17 @@ inside of and outside of chord construct."
         music)
       ;; not in <...>, so use overrides
       (make-sequential-music
         music)
       ;; not in <...>, so use overrides
       (make-sequential-music

-        (list
-          (override-head-style heads style)
-          music
-          (revert-head-style heads)))))
+       (list
+        (override-head-style heads style)
+        music
+        (revert-head-style heads)))))

 
 

- (define-public (set-mus-properties! m alist)
+(define-public (set-mus-properties! m alist)

   "Set all of @var{alist} as properties of @var{m}."
   (if (pair? alist)
       (begin
   "Set all of @var{alist} as properties of @var{m}."
   (if (pair? alist)
       (begin

-       (set! (ly:music-property m (caar alist)) (cdar alist))
-       (set-mus-properties! m (cdr alist)))))
+        (set! (ly:music-property m (caar alist)) (cdar alist))
+        (set-mus-properties! m (cdr alist)))))

 
 (define-public (music-separator? m)
   "Is @var{m} a separator?"
 
 (define-public (music-separator? m)
   "Is @var{m} a separator?"


@@ -612,7 +698,7 @@ inside of and outside of chord construct."
 
 ;;; expanding repeat chords
 (define-public (copy-repeat-chord original-chord repeat-chord duration
 
 ;;; expanding repeat chords
 (define-public (copy-repeat-chord original-chord repeat-chord duration

-                                 event-types)
+                                  event-types)

   "Copies all events in @var{event-types} (be sure to include
 @code{rhythmic-events}) from @var{original-chord} over to
 @var{repeat-chord} with their articulations filtered as well.  Any
   "Copies all events in @var{event-types} (be sure to include
 @code{rhythmic-events}) from @var{original-chord} over to
 @var{repeat-chord} with their articulations filtered as well.  Any


@@ -624,47 +710,48 @@ duration is replaced with the specified @var{duration}."
 
   (define (keep-element? m)
     (any (lambda (t) (music-is-of-type? m t))
 
   (define (keep-element? m)
     (any (lambda (t) (music-is-of-type? m t))

-        event-types))
+         event-types))

   (define origin (ly:music-property repeat-chord 'origin #f))
   (define (set-origin! l)
     (if origin
   (define origin (ly:music-property repeat-chord 'origin #f))
   (define (set-origin! l)
     (if origin

-       (for-each (lambda (m) (set! (ly:music-property m 'origin) origin)) l))
+        (for-each (lambda (m) (set! (ly:music-property m 'origin) origin)) l))

     l)
 
   (for-each
    (lambda (field)
      (for-each (lambda (e)
     l)
 
   (for-each
    (lambda (field)
      (for-each (lambda (e)

-                (for-each (lambda (x)
-                            (set! event-types (delq x event-types)))
-                          (ly:music-property e 'types)))
-              (ly:music-property repeat-chord field)))
+                 (for-each (lambda (x)
+                             (set! event-types (delq x event-types)))
+                           (ly:music-property e 'types)))
+               (ly:music-property repeat-chord field)))

    '(elements articulations))
 
   ;; now treat the elements
   (set! (ly:music-property repeat-chord 'elements)
    '(elements articulations))
 
   ;; now treat the elements
   (set! (ly:music-property repeat-chord 'elements)

-       (let ((elts
-              (set-origin! (ly:music-deep-copy
-                            (filter keep-element?
-                                    (ly:music-property original-chord
-                                                       'elements))))))
-         (for-each
-          (lambda (m)
-            (let ((arts (ly:music-property m 'articulations)))
-              (if (pair? arts)
-                  (set! (ly:music-property m 'articulations)
-                        (set-origin! (filter! keep-element? arts))))
-              (if (ly:duration? (ly:music-property m 'duration))
-                  (set! (ly:music-property m 'duration) duration))))
-          elts)
-         (append! elts (ly:music-property repeat-chord 'elements))))
+        (let ((elts
+               (set-origin! (ly:music-deep-copy
+                             (filter keep-element?
+                                     (ly:music-property original-chord
+                                                        'elements))))))
+          (for-each
+           (lambda (m)
+             (let ((arts (ly:music-property m 'articulations)))
+               (if (pair? arts)
+                   (set! (ly:music-property m 'articulations)
+                         (set-origin! (filter! keep-element? arts))))
+               (if (ly:duration? (ly:music-property m 'duration))
+                   (set! (ly:music-property m 'duration) duration))))
+           elts)
+          (append! elts (ly:music-property repeat-chord 'elements))))

   (let ((arts (filter keep-element?
   (let ((arts (filter keep-element?

-                     (ly:music-property original-chord
-                                        'articulations))))
+                      (ly:music-property original-chord
+                                         'articulations))))

     (if (pair? arts)
     (if (pair? arts)

-       (set! (ly:music-property repeat-chord 'articulations)
-             (append!
-              (set-origin! (ly:music-deep-copy arts))
-              (ly:music-property repeat-chord 'articulations))))))
+        (set! (ly:music-property repeat-chord 'articulations)
+              (append!
+               (set-origin! (ly:music-deep-copy arts))
+               (ly:music-property repeat-chord 'articulations)))))
+  repeat-chord)

 
 
 (define-public (expand-repeat-chords! event-types music)
 
 
 (define-public (expand-repeat-chords! event-types music)


@@ -673,26 +760,92 @@ having a duration in @code{duration}) with the notes from their
 respective predecessor chord."
   (let loop ((music music) (last-chord #f))
     (if (music-is-of-type? music 'event-chord)
 respective predecessor chord."
   (let loop ((music music) (last-chord #f))
     (if (music-is-of-type? music 'event-chord)

-       (let ((chord-repeat (ly:music-property music 'duration)))
-         (cond
-          ((not (ly:duration? chord-repeat))
-           (if (any (lambda (m) (ly:duration?
-                                 (ly:music-property m 'duration)))
-                    (ly:music-property music 'elements))
-               music
-               last-chord))
-          (last-chord
-           (set! (ly:music-property music 'duration) '())
-           (copy-repeat-chord last-chord music chord-repeat event-types)
-           music)
-          (else
-           (ly:music-warning music (_ "Bad chord repetition"))
-           #f)))
-       (let ((elt (ly:music-property music 'element)))
-         (fold loop (if (ly:music? elt) (loop elt last-chord) last-chord)
-               (ly:music-property music 'elements)))))
+        (let ((chord-repeat (ly:music-property music 'duration)))
+          (cond
+           ((not (ly:duration? chord-repeat))
+            (if (any (lambda (m) (ly:duration?
+                                  (ly:music-property m 'duration)))
+                     (ly:music-property music 'elements))
+                music
+                last-chord))
+           (last-chord
+            (set! (ly:music-property music 'duration) '())
+            (copy-repeat-chord last-chord music chord-repeat event-types))
+           (else
+            (ly:music-warning music (_ "Bad chord repetition"))
+            #f)))
+        (let ((elt (ly:music-property music 'element)))
+          (fold loop (if (ly:music? elt) (loop elt last-chord) last-chord)
+                (ly:music-property music 'elements)))))

   music)
 
   music)
 

+;;; This does _not_ copy any articulations.  Rationale: one main
+;;; incentive for pitch-repeating durations is after ties, such that
+;;; 4~2~8. can stand in for a 15/16 note in \partial 4 position.  In
+;;; this use case, any repeated articulations will be a nuisance.
+;;;
+;;; String assignments in TabStaff might seem like a worthwhile
+;;; exception, but they would be better tackled by the respective
+;;; engravers themselves (see issue 3662).
+;;;
+;;; Repeating chords as well seems problematic for things like
+;;; \score {
+;;;   <<
+;;;     \new Staff { c4 c c <c e> }
+;;;     \new RhythmicStaff { 4 4 4 4 }
+;;;   >>
+;;; }
+;;;
+;;; However, because of MIDI it is not advisable to use RhythmicStaff
+;;; without any initial pitch/drum-type.  For music functions taking
+;;; pure rhythms as an argument, the running of expand-repeat-notes!
+;;; at scorification time is irrelevant: at that point of time, the
+;;; music function has already run.
+
+(define-public (expand-repeat-notes! music)
+  "Walks through @var{music} and gives pitchless notes (not having a
+pitch in code{pitch} or a drum type in @code{drum-type}) the pitch(es)
+from the predecessor note/chord if available."
+  (let ((last-pitch #f))
+    (map-some-music
+     (lambda (m)
+       (define (set-and-ret last)
+         (set! last-pitch last)
+         m)
+       (cond
+        ((music-is-of-type? m 'event-chord)
+         (set-and-ret m))
+        ((music-is-of-type? m 'note-event)
+         (cond
+          ((or (ly:music-property m 'pitch #f)
+               (ly:music-property m 'drum-type #f))
+           => set-and-ret)
+          ;; ok, naked rhythm.  Go through the various cases of
+          ;; last-pitch
+          ;; nothing available: just keep as-is
+          ((not last-pitch) m)
+          ((ly:pitch? last-pitch)
+           (set! (ly:music-property m 'pitch) last-pitch)
+           m)
+          ((symbol? last-pitch)
+           (set! (ly:music-property m 'drum-type) last-pitch)
+           m)
+          ;; Ok, this is the big bad one: the reference is a chord.
+          ;; For now, we use the repeat chord logic.  That's not
+          ;; really efficient as cleaning out all articulations is
+          ;; quite simpler than what copy-repeat-chord does.
+          (else
+           (copy-repeat-chord last-pitch
+                              (make-music 'EventChord
+                                          'elements
+                                          (ly:music-property m 'articulations)
+                                          'origin
+                                          (ly:music-property m 'origin))
+                              (ly:music-property m 'duration)
+                              '(rhythmic-event)))))
+        (else #f)))
+     music)))
+

 ;;; splitting chords into voices.
 (define (voicify-list lst number)
   "Make a list of Musics.
 ;;; splitting chords into voices.
 (define (voicify-list lst number)
   "Make a list of Musics.


@@ -705,17 +858,17 @@ NUMBER is 0-base, i.e., Voice=1 (upstems) has number 0.
   (if (null? lst)
       '()
       (cons (context-spec-music
   (if (null? lst)
       '()
       (cons (context-spec-music

-            (make-sequential-music
-             (list (make-voice-props-set number)
-                   (make-simultaneous-music (car lst))))
-            'Bottom  (number->string (1+ number)))
-           (voicify-list (cdr lst) (1+ number)))))
+             (make-sequential-music
+              (list (make-voice-props-set number)
+                    (make-simultaneous-music (car lst))))
+             'Bottom  (number->string (1+ number)))
+            (voicify-list (cdr lst) (1+ number)))))

 
 (define (voicify-chord ch)
   "Split the parts of a chord into different Voices using separator"
   (let ((es (ly:music-property ch 'elements)))
     (set! (ly:music-property  ch 'elements)
 
 (define (voicify-chord ch)
   "Split the parts of a chord into different Voices using separator"
   (let ((es (ly:music-property ch 'elements)))
     (set! (ly:music-property  ch 'elements)

-         (voicify-list (split-list-by-separator es music-separator?) 0))
+          (voicify-list (split-list-by-separator es music-separator?) 0))

     ch))
 
 (define-public (voicify-music m)
     ch))
 
 (define-public (voicify-music m)


@@ -723,15 +876,15 @@ NUMBER is 0-base, i.e., Voice=1 (upstems) has number 0.
   (if (not (ly:music? m))
       (ly:error (_ "music expected: ~S") m))
   (let ((es (ly:music-property m 'elements))
   (if (not (ly:music? m))
       (ly:error (_ "music expected: ~S") m))
   (let ((es (ly:music-property m 'elements))

-       (e (ly:music-property m 'element)))
+        (e (ly:music-property m 'element)))

 
     (if (pair? es)
 
     (if (pair? es)

-       (set! (ly:music-property m 'elements) (map voicify-music es)))
+        (set! (ly:music-property m 'elements) (map voicify-music es)))

     (if (ly:music? e)
     (if (ly:music? e)

-       (set! (ly:music-property m 'element)  (voicify-music e)))
+        (set! (ly:music-property m 'element)  (voicify-music e)))

     (if (and (equal? (ly:music-property m 'name) 'SimultaneousMusic)
     (if (and (equal? (ly:music-property m 'name) 'SimultaneousMusic)

-            (reduce (lambda (x y ) (or x y)) #f (map music-separator? es)))
-       (set! m (context-spec-music (voicify-chord m) 'Staff)))
+             (any music-separator? es))
+        (set! m (context-spec-music (voicify-chord m) 'Staff)))

     m))
 
 (define-public (empty-music)
     m))
 
 (define-public (empty-music)


@@ -752,7 +905,7 @@ NUMBER is 0-base, i.e., Voice=1 (upstems) has number 0.
 @code{\\applyoutput #(set-output-property 'Clef 'extra-offset '(0 . 1))}"
   (let ((meta (ly:grob-property grob 'meta)))
     (if (equal? (assoc-get 'name meta) grob-name)
 @code{\\applyoutput #(set-output-property 'Clef 'extra-offset '(0 . 1))}"
   (let ((meta (ly:grob-property grob 'meta)))
     (if (equal? (assoc-get 'name meta) grob-name)

-       (set! (ly:grob-property grob symbol) val))))
+        (set! (ly:grob-property grob symbol) val))))

 
 
 (define-public (skip->rest mus)
 
 
 (define-public (skip->rest mus)


@@ -760,39 +913,65 @@ NUMBER is 0-base, i.e., Voice=1 (upstems) has number 0.
 @code{SkipEvent}.  Useful for extracting parts from crowded scores."
 
   (if  (memq (ly:music-property mus 'name) '(SkipEvent SkipMusic))
 @code{SkipEvent}.  Useful for extracting parts from crowded scores."
 
   (if  (memq (ly:music-property mus 'name) '(SkipEvent SkipMusic))

-   (make-music 'RestEvent 'duration (ly:music-property mus 'duration))
-   mus))
+       (make-music 'RestEvent 'duration (ly:music-property mus 'duration))
+       mus))

 
 
 (define-public (music-has-type music type)
   (memq type (ly:music-property music 'types)))
 
 
 
 (define-public (music-has-type music type)
   (memq type (ly:music-property music 'types)))
 

-(define-public (music-clone music)
-  (define (alist->args alist acc)
-    (if (null? alist)
-       acc
-       (alist->args (cdr alist)
-                    (cons (caar alist) (cons (cdar alist) acc)))))
-
-  (apply
-   make-music
-   (ly:music-property music 'name)
-   (alist->args (ly:music-mutable-properties music) '())))
+(define-public (music-clone music . music-properties)
+  "Clone @var{music} and set properties according to
+@var{music-properties}, a list of alternating property symbols and
+values:
+@example\n(music-clone start-span 'span-direction STOP)
+@end example
+Only properties that are not overriden by @var{music-properties} are
+actually fully cloned."
+  (let ((old-props (list-copy (ly:music-mutable-properties music)))
+        (new-props '())
+        (m (ly:make-music (ly:prob-immutable-properties music))))
+    (define (set-props mus-props)
+      (if (and (not (null? mus-props))
+               (not (null? (cdr mus-props))))
+          (begin
+            (set! old-props (assq-remove! old-props (car mus-props)))
+            (set! new-props
+                  (assq-set! new-props
+                             (car mus-props) (cadr mus-props)))
+            (set-props (cddr mus-props)))))
+    (set-props music-properties)
+    (for-each
+     (lambda (pair)
+       (set! (ly:music-property m (car pair))
+             (ly:music-deep-copy (cdr pair))))
+     old-props)
+    (for-each
+     (lambda (pair)
+       (set! (ly:music-property m (car pair)) (cdr pair)))
+     new-props)
+    m))

 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; warn for bare chords at start.
 
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; warn for bare chords at start.
 

-(define-public (ly:music-message music msg)
+(define-public (ly:music-message music msg . rest)

   (let ((ip (ly:music-property music 'origin)))
     (if (ly:input-location? ip)
   (let ((ip (ly:music-property music 'origin)))
     (if (ly:input-location? ip)

-        (ly:input-message ip msg)
-        (ly:message msg))))
+        (apply ly:input-message ip msg rest)
+        (apply ly:message msg rest))))

 
 

-(define-public (ly:music-warning music msg)
+(define-public (ly:music-warning music msg . rest)

   (let ((ip (ly:music-property music 'origin)))
     (if (ly:input-location? ip)
   (let ((ip (ly:music-property music 'origin)))
     (if (ly:input-location? ip)

-        (ly:input-warning ip msg)
-        (ly:warning msg))))
+        (apply ly:input-warning ip msg rest)
+        (apply ly:warning msg rest))))
+
+(define-public (ly:event-warning event msg . rest)
+  (let ((ip (ly:event-property event 'origin)))
+    (if (ly:input-location? ip)
+        (apply ly:input-warning ip msg rest)
+        (apply ly:warning msg rest))))

 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;


@@ -802,7 +981,7 @@ NUMBER is 0-base, i.e., Voice=1 (upstems) has number 0.
 (define (vector-extend v x)
   "Make a new vector consisting of V, with X added to the end."
   (let* ((n (vector-length v))
 (define (vector-extend v x)
   "Make a new vector consisting of V, with X added to the end."
   (let* ((n (vector-length v))

-        (nv (make-vector (+ n 1) '())))
+         (nv (make-vector (+ n 1) '())))

     (vector-move-left! v 0 n nv 0)
     (vector-set! nv n x)
     nv))
     (vector-move-left! v 0 n nv 0)
     (vector-set! nv n x)
     nv))


@@ -823,12 +1002,12 @@ NUMBER is 0-base, i.e., Voice=1 (upstems) has number 0.
 (define-public (add-grace-property context-name grob sym val)
   "Set @var{sym}=@var{val} for @var{grob} in @var{context-name}."
   (define (set-prop context)
 (define-public (add-grace-property context-name grob sym val)
   "Set @var{sym}=@var{val} for @var{grob} in @var{context-name}."
   (define (set-prop context)

-    (let* ((where (ly:context-property-where-defined context 'graceSettings))
-          (current (ly:context-property where 'graceSettings))
-          (new-settings (append current
-                                (list (list context-name grob sym val)))))
+    (let* ((where (or (ly:context-find context context-name) context))
+           (current (ly:context-property where 'graceSettings))
+           (new-settings (append current
+                                 (list (list context-name grob sym val)))))

       (ly:context-set-property! where 'graceSettings new-settings)))
       (ly:context-set-property! where 'graceSettings new-settings)))

-  (context-spec-music (make-apply-context set-prop) 'Voice))
+  (make-apply-context set-prop))

 
 (define-public (remove-grace-property context-name grob sym)
   "Remove all @var{sym} for @var{grob} in @var{context-name}."
 
 (define-public (remove-grace-property context-name grob sym)
   "Remove all @var{sym} for @var{grob} in @var{context-name}."


@@ -837,18 +1016,17 @@ NUMBER is 0-base, i.e., Voice=1 (upstems) has number 0.
          (eq? (cadr property) grob)
          (eq? (caddr property) sym)))
   (define (delete-prop context)
          (eq? (cadr property) grob)
          (eq? (caddr property) sym)))
   (define (delete-prop context)

-    (let* ((where (ly:context-property-where-defined context 'graceSettings))
-          (current (ly:context-property where 'graceSettings))
+    (let* ((where (or (ly:context-find context context-name) context))
+           (current (ly:context-property where 'graceSettings))

            (prop-settings (filter
            (prop-settings (filter

-                            (lambda(x) (sym-grob-context? x sym grob context-name))
-                            current))
-          (new-settings current))
+                           (lambda(x) (sym-grob-context? x sym grob context-name))
+                           current))
+           (new-settings current))

       (for-each (lambda(x)
       (for-each (lambda(x)

-                 (set! new-settings (delete x new-settings)))
-               prop-settings)
+                  (set! new-settings (delete x new-settings)))
+                prop-settings)

       (ly:context-set-property! where 'graceSettings new-settings)))
       (ly:context-set-property! where 'graceSettings new-settings)))

-  (context-spec-music (make-apply-context delete-prop) 'Voice))
-
+  (make-apply-context delete-prop))

 
 
 (defmacro-public def-grace-function (start stop . docstring)
 
 
 (defmacro-public def-grace-function (start stop . docstring)


@@ -856,11 +1034,11 @@ NUMBER is 0-base, i.e., Voice=1 (upstems) has number 0.
   `(define-music-function (parser location music) (ly:music?)
      ,@docstring
      (make-music 'GraceMusic
   `(define-music-function (parser location music) (ly:music?)
      ,@docstring
      (make-music 'GraceMusic

-                'origin location
-                'element (make-music 'SequentialMusic
-                                     'elements (list (ly:music-deep-copy ,start)
-                                                     music
-                                                     (ly:music-deep-copy ,stop))))))
+                 'origin location
+                 'element (make-music 'SequentialMusic
+                                      'elements (list (ly:music-deep-copy ,start)
+                                                      music
+                                                      (ly:music-deep-copy ,stop))))))

 
 (defmacro-public define-syntax-function (type args signature . body)
   "Helper macro for `ly:make-music-function'.
 
 (defmacro-public define-syntax-function (type args signature . body)
   "Helper macro for `ly:make-music-function'.


@@ -884,24 +1062,37 @@ predicates require the parameter to be entered as Scheme expression.
 predicates, to be used in case of a type error in arguments or
 result."
 
 predicates, to be used in case of a type error in arguments or
 result."
 

+  (define (currying-lambda args doc-string? body)
+    (if (and (pair? args)
+             (pair? (car args)))
+        (currying-lambda (car args) doc-string?
+                         `((lambda ,(cdr args) ,@body)))
+        (if doc-string?
+            `(lambda ,args ,doc-string? ,@body)
+            `(lambda ,args ,@body))))
+

   (set! signature (map (lambda (pred)
   (set! signature (map (lambda (pred)

-                        (if (pair? pred)
-                            `(cons ,(car pred)
-                                   ,(and (pair? (cdr pred)) (cadr pred)))
-                            pred))
-                      (cons type signature)))
-  (if (and (pair? body) (pair? (car body)) (eqv? '_i (caar body)))
-      ;; When the music function definition contains a i10n doc string,
-      ;; (_i "doc string"), keep the literal string only
-      (let ((docstring (cadar body))
-           (body (cdr body)))
-       `(ly:make-music-function (list ,@signature)
-                                (lambda ,args
-                                  ,docstring
-                                  ,@body)))
-      `(ly:make-music-function (list ,@signature)
-                              (lambda ,args
-                                ,@body))))
+                         (if (pair? pred)
+                             `(cons ,(car pred)
+                                    ,(and (pair? (cdr pred)) (cadr pred)))
+                             pred))
+                       (cons type signature)))
+
+  (let ((docstring
+         (and (pair? body) (pair? (cdr body))
+              (if (string? (car body))
+                  (car body)
+                  (and (pair? (car body))
+                       (eq? '_i (caar body))
+                       (pair? (cdar body))
+                       (string? (cadar body))
+                       (null? (cddar body))
+                       (cadar body))))))
+    ;; When the music function definition contains an i10n doc string,
+    ;; (_i "doc string"), keep the literal string only
+    `(ly:make-music-function
+      (list ,@signature)
+      ,(currying-lambda args docstring (if docstring (cdr body) body)))))

 
 (defmacro-public define-music-function rest
   "Defining macro returning music functions.
 
 (defmacro-public define-music-function rest
   "Defining macro returning music functions.


@@ -989,57 +1180,57 @@ set to the @code{location} parameter."
 
   (if (vector? (ly:music-property quote-music 'quoted-events))
       (let* ((dir (ly:music-property quote-music 'quoted-voice-direction))
 
   (if (vector? (ly:music-property quote-music 'quoted-events))
       (let* ((dir (ly:music-property quote-music 'quoted-voice-direction))

-            (clef (ly:music-property quote-music 'quoted-music-clef #f))
-            (main-voice (case dir ((1) 1) ((-1) 0) (else #f)))
-            (cue-voice (and main-voice (- 1 main-voice)))
-            (main-music (ly:music-property quote-music 'element))
-            (return-value quote-music))
-
-       (if main-voice
-           (set! (ly:music-property quote-music 'element)
-                 (make-sequential-music
-                  (list
-                   (make-voice-props-override main-voice)
-                   main-music
-                   (make-voice-props-revert)))))
-
-       ;; if we have stem dirs, change both quoted and main music
-       ;; to have opposite stems.
-
-       ;; cannot context-spec Quote-music, since context
-       ;; for the quotes is determined in the iterator.
-
-       (make-sequential-music
-        (delq! #f
-               (list
-                (and clef (make-cue-clef-set clef))
-
-                ;; Need to establish CueVoice context even in #CENTER case
-                (context-spec-music
-                 (if cue-voice
-                     (make-voice-props-override cue-voice)
-                     (make-music 'Music))
-                 'CueVoice "cue")
-                quote-music
-                (and cue-voice
-                     (context-spec-music
-                      (make-voice-props-revert) 'CueVoice "cue"))
-                (and clef (make-cue-clef-unset))))))
+             (clef (ly:music-property quote-music 'quoted-music-clef #f))
+             (main-voice (case dir ((1) 1) ((-1) 0) (else #f)))
+             (cue-voice (and main-voice (- 1 main-voice)))
+             (cue-type (ly:music-property quote-music 'quoted-context-type #f))
+             (cue-id (ly:music-property quote-music 'quoted-context-id))
+             (main-music (ly:music-property quote-music 'element))
+             (return-value quote-music))
+
+        (if main-voice
+            (set! (ly:music-property quote-music 'element)
+                  (make-sequential-music
+                   (list
+                    (make-voice-props-override main-voice)
+                    main-music
+                    (make-voice-props-revert)))))
+
+        ;; if we have stem dirs, change both quoted and main music
+        ;; to have opposite stems.
+
+        ;; cannot context-spec Quote-music, since context
+        ;; for the quotes is determined in the iterator.
+
+        (make-sequential-music
+         (delq! #f
+                (list
+                 (and clef (make-cue-clef-set clef))
+                 (and cue-type cue-voice
+                      (context-spec-music
+                       (make-voice-props-override cue-voice)
+                       cue-type cue-id))
+                 quote-music
+                 (and cue-type cue-voice
+                      (context-spec-music
+                       (make-voice-props-revert)
+                       cue-type cue-id))
+                 (and clef (make-cue-clef-unset))))))

       quote-music))
 
 (define-public ((quote-substitute quote-tab) music)
   (let* ((quoted-name (ly:music-property music 'quoted-music-name))
       quote-music))
 
 (define-public ((quote-substitute quote-tab) music)
   (let* ((quoted-name (ly:music-property music 'quoted-music-name))

-        (quoted-vector (and (string? quoted-name)
-                            (hash-ref quote-tab quoted-name #f))))
+         (quoted-vector (and (string? quoted-name)
+                             (hash-ref quote-tab quoted-name #f))))

 
 
     (if (string? quoted-name)
 
 
     (if (string? quoted-name)

-       (if (vector? quoted-vector)
-           (begin
-             (set! (ly:music-property music 'quoted-events) quoted-vector)
-             (set! (ly:music-property music 'iterator-ctor)
-                   ly:quote-iterator::constructor))
-           (ly:music-warning music (ly:format (_ "cannot find quoted music: `~S'") quoted-name))))
+        (if (vector? quoted-vector)
+            (begin
+              (set! (ly:music-property music 'quoted-events) quoted-vector)
+              (set! (ly:music-property music 'iterator-ctor)
+                    ly:quote-iterator::constructor))
+            (ly:music-warning music (ly:format (_ "cannot find quoted music: `~S'") quoted-name))))

     music))
 
 
     music))
 
 


@@ -1057,8 +1248,8 @@ set to the @code{location} parameter."
   (define found #f)
   (define (signal m)
     (if (and (ly:music? m)
   (define found #f)
   (define (signal m)
     (if (and (ly:music? m)

-            (eq? (ly:music-property m 'error-found) #t))
-       (set! found #t)))
+             (eq? (ly:music-property m 'error-found) #t))
+        (set! found #t)))

 
   (for-each signal (ly:music-property music 'elements))
   (signal (ly:music-property music 'element))
 
   (for-each signal (ly:music-property music 'elements))
   (signal (ly:music-property music 'element))


@@ -1069,27 +1260,27 @@ set to the @code{location} parameter."
 
 (define (precompute-music-length music)
   (set! (ly:music-property music 'length)
 
 (define (precompute-music-length music)
   (set! (ly:music-property music 'length)

-       (ly:music-length music))
+        (ly:music-length music))

   music)
 
 (define-public (make-duration-of-length moment)
   music)
 
 (define-public (make-duration-of-length moment)

- "Make duration of the given @code{moment} length."
- (ly:make-duration 0 0
-  (ly:moment-main-numerator moment)
-  (ly:moment-main-denominator moment)))
+  "Make duration of the given @code{moment} length."
+  (ly:make-duration 0 0
+                    (ly:moment-main-numerator moment)
+                    (ly:moment-main-denominator moment)))

 
 (define (make-skipped moment bool)
 
 (define (make-skipped moment bool)

- "Depending on BOOL, set or unset skipTypesetting,
+  "Depending on BOOL, set or unset skipTypesetting,

 then make SkipMusic of the given MOMENT length, and
 then revert skipTypesetting."
 then make SkipMusic of the given MOMENT length, and
 then revert skipTypesetting."

- (make-sequential-music
-  (list
-   (context-spec-music (make-property-set 'skipTypesetting bool)
-    'Score)
-   (make-music 'SkipMusic 'duration
-    (make-duration-of-length moment))
-   (context-spec-music (make-property-set 'skipTypesetting (not bool))
-    'Score))))
+  (make-sequential-music
+   (list
+    (context-spec-music (make-property-set 'skipTypesetting bool)
+                        'Score)
+    (make-music 'SkipMusic 'duration
+                (make-duration-of-length moment))
+    (context-spec-music (make-property-set 'skipTypesetting (not bool))
+                        'Score))))

 
 (define (skip-as-needed music parser)
   "Replace MUSIC by
 
 (define (skip-as-needed music parser)
   "Replace MUSIC by


@@ -1107,9 +1298,9 @@ then revert skipTypesetting."
       ((show-last (ly:parser-lookup parser 'showLastLength))
        (show-first (ly:parser-lookup parser 'showFirstLength))
        (show-last-length (and (ly:music? show-last)
       ((show-last (ly:parser-lookup parser 'showLastLength))
        (show-first (ly:parser-lookup parser 'showFirstLength))
        (show-last-length (and (ly:music? show-last)

-                             (ly:music-length show-last)))
+                              (ly:music-length show-last)))

        (show-first-length (and (ly:music? show-first)
        (show-first-length (and (ly:music? show-first)

-                              (ly:music-length show-first)))
+                               (ly:music-length show-first)))

        (orig-length (ly:music-length music)))
 
     ;;FIXME: if using either showFirst- or showLastLength,
        (orig-length (ly:music-length music)))
 
     ;;FIXME: if using either showFirst- or showLastLength,


@@ -1153,12 +1344,13 @@ then revert skipTypesetting."
      (else music))))
 
 
      (else music))))
 
 

-(define-public toplevel-music-functions
+(define-session-public toplevel-music-functions

   (list
    (lambda (music parser) (expand-repeat-chords!
   (list
    (lambda (music parser) (expand-repeat-chords!

-                          (cons 'rhythmic-event
-                                (ly:parser-lookup parser '$chord-repeat-events))
-                          music))
+                           (cons 'rhythmic-event
+                                 (ly:parser-lookup parser '$chord-repeat-events))
+                           music))
+   (lambda (music parser) (expand-repeat-notes! music))

    (lambda (music parser) (voicify-music music))
    (lambda (x parser) (music-map music-check-error x))
    (lambda (x parser) (music-map precompute-music-length x))
    (lambda (music parser) (voicify-music music))
    (lambda (x parser) (music-map music-check-error x))
    (lambda (x parser) (music-map precompute-music-length x))


@@ -1171,7 +1363,7 @@ then revert skipTypesetting."
 
    (lambda (x parser)
      (skip-as-needed x parser)
 
    (lambda (x parser)
      (skip-as-needed x parser)

-   )))
+     )))

 
 ;;;;;;;;;;
 ;;; general purpose music functions
 
 ;;;;;;;;;;
 ;;; general purpose music functions


@@ -1179,9 +1371,9 @@ then revert skipTypesetting."
 (define (shift-octave pitch octave-shift)
   (_i "Add @var{octave-shift} to the octave of @var{pitch}.")
   (ly:make-pitch
 (define (shift-octave pitch octave-shift)
   (_i "Add @var{octave-shift} to the octave of @var{pitch}.")
   (ly:make-pitch

-     (+ (ly:pitch-octave pitch) octave-shift)
-     (ly:pitch-notename pitch)
-     (ly:pitch-alteration pitch)))
+   (+ (ly:pitch-octave pitch) octave-shift)
+   (ly:pitch-notename pitch)
+   (ly:pitch-alteration pitch)))

 
 
 ;;;;;;;;;;;;;;;;;
 
 
 ;;;;;;;;;;;;;;;;;


@@ -1190,10 +1382,10 @@ then revert skipTypesetting."
 (define (apply-durations lyric-music durations)
   (define (apply-duration music)
     (if (and (not (equal? (ly:music-length music) ZERO-MOMENT))
 (define (apply-durations lyric-music durations)
   (define (apply-duration music)
     (if (and (not (equal? (ly:music-length music) ZERO-MOMENT))

-            (ly:duration?  (ly:music-property music 'duration)))
-       (begin
-         (set! (ly:music-property music 'duration) (car durations))
-         (set! durations (cdr durations)))))
+             (ly:duration?  (ly:music-property music 'duration)))
+        (begin
+          (set! (ly:music-property music 'duration) (car durations))
+          (set! durations (cdr durations)))))

 
   (music-map apply-duration lyric-music))
 
 
   (music-map apply-duration lyric-music))
 


@@ -1215,16 +1407,16 @@ 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)
 
 Returns @code{#f} or the reason for the invalidation, a symbol."
   (let* ((def (if (pair? alteration-def)

-                 (car alteration-def)
-                 alteration-def)))
+                  (car alteration-def)
+                  alteration-def)))

     (and (symbol? def) def)))
 
 (define (extract-alteration alteration-def)
   (cond ((number? 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)))
+         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
 
 (define (check-pitch-against-signature context pitch barnum laziness octaveness)
   "Checks the need for an accidental and a @q{restore} accidental against


@@ -1235,50 +1427,50 @@ 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)
 @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))))
+                              ((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)
 
     ;; 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))))))
+          (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)
 
     ;; 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))
+           from-same-octave
+           (recent-enough? barnum from-same-octave laziness))

       (set! previous-alteration from-same-octave))
 
      ;; from any octave?
      ((and ignore-octave
       (set! previous-alteration from-same-octave))
 
      ;; from any octave?
      ((and ignore-octave

-          from-other-octaves
-          (recent-enough? barnum from-other-octaves laziness))
+           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
       (set! previous-alteration from-other-octaves))
 
      ;; not recent enough, extract from key signature/local key signature


@@ -1286,18 +1478,18 @@ specifies whether accidentals should be canceled in different octaves."
       (set! previous-alteration from-key-sig)))
 
     (if (accidental-invalid? previous-alteration)
       (set! previous-alteration from-key-sig)))
 
     (if (accidental-invalid? previous-alteration)

-       (set! need-accidental #t)
+        (set! need-accidental #t)

 
 

-       (let* ((prev-alt (extract-alteration previous-alteration))
-              (this-alt (ly:pitch-alteration pitch)))
+        (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))))))
+          (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)))
 
 
     (cons need-restore need-accidental)))
 


@@ -1358,8 +1550,8 @@ See @code{key-entry-notename} for details."
 For convenience, returns @code{0} if entry is @code{#f}."
   (if entry
       (if (number? (cdr entry))
 For convenience, returns @code{0} if entry is @code{#f}."
   (if entry
       (if (number? (cdr entry))

-         (cdr entry)
-         (cadr entry))
+          (cdr entry)
+          (cadr entry))

       0))
 
 (define-public (find-pitch-entry keysig pitch accept-global accept-local)
       0))
 
 (define-public (find-pitch-entry keysig pitch accept-global accept-local)


@@ -1369,17 +1561,17 @@ For convenience, returns @code{0} if entry is @code{#f}."
 If no matching entry is found, @var{#f} is returned."
   (and (pair? keysig)
        (let* ((entry (car keysig))
 If no matching entry is found, @var{#f} is returned."
   (and (pair? keysig)
        (let* ((entry (car keysig))

-             (entryoct (key-entry-octave entry))
-             (entrynn (key-entry-notename entry))
-             (nn (ly:pitch-notename pitch)))
-        (if (and (equal? nn entrynn)
-                 (or (not entryoct)
-                     (= entryoct (ly:pitch-octave pitch)))
-                 (if (key-entry-bar-number entry)
-                     accept-local
-                     accept-global))
-            entry
-            (find-pitch-entry (cdr keysig) pitch accept-global accept-local)))))
+              (entryoct (key-entry-octave entry))
+              (entrynn (key-entry-notename entry))
+              (nn (ly:pitch-notename pitch)))
+         (if (and (equal? nn entrynn)
+                  (or (not entryoct)
+                      (= entryoct (ly:pitch-octave pitch)))
+                  (if (key-entry-bar-number entry)
+                      accept-local
+                      accept-global))
+             entry
+             (find-pitch-entry (cdr keysig) pitch accept-global accept-local)))))

 
 (define-public (neo-modern-accidental-rule context pitch barnum measurepos)
   "An accidental rule that typesets an accidental if it differs from the
 
 (define-public (neo-modern-accidental-rule context pitch barnum measurepos)
   "An accidental rule that typesets an accidental if it differs from the


@@ -1387,39 +1579,39 @@ key signature @emph{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 note name."
   (let* ((keysig (ly:context-property context 'localKeySignature))
 staff line.  This rule should not be used alone because it does neither
 look at bar lines nor different accidentals at the same note name."
   (let* ((keysig (ly:context-property context 'localKeySignature))

-        (entry (find-pitch-entry keysig pitch #t #t)))
+         (entry (find-pitch-entry keysig pitch #t #t)))

     (if (not entry)
     (if (not entry)

-       (cons #f #f)
-       (let* ((global-entry (find-pitch-entry keysig pitch #t #f))
-              (key-acc (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)))))))))
+        (cons #f #f)
+        (let* ((global-entry (find-pitch-entry keysig pitch #t #f))
+               (key-acc (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 @emph{and} does not directly follow a note
 on the same staff line."
   (let* ((keysig (ly:context-property context 'localKeySignature))
 
 (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 @emph{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)))
+         (entry (find-pitch-entry keysig pitch #t #t)))

     (if (not entry)
     (if (not entry)

-       (cons #f #f)
-       (let* ((entrymp (key-entry-measure-position entry))
-              (entrybn (key-entry-bar-number entry)))
-         (cons #f (not (and (equal? entrybn barnum) (equal? entrymp measurepos))))))))
+        (cons #f #f)
+        (let* ((entrymp (key-entry-measure-position entry))
+               (entrybn (key-entry-bar-number entry)))
+          (cons #f (not (and (equal? entrybn barnum) (equal? entrymp measurepos))))))))

 
 (define-public (set-accidentals-properties extra-natural
 
 (define-public (set-accidentals-properties extra-natural

-                                          auto-accs auto-cauts
-                                          context)
+                                           auto-accs auto-cauts
+                                           context)

   (context-spec-music
    (make-sequential-music
     (append (if (boolean? extra-natural)
   (context-spec-music
    (make-sequential-music
     (append (if (boolean? extra-natural)

-               (list (make-property-set 'extraNatural extra-natural))
-               '())
-           (list (make-property-set 'autoAccidentals auto-accs)
-                 (make-property-set 'autoCautionaries auto-cauts))))
+                (list (make-property-set 'extraNatural extra-natural))
+                '())
+            (list (make-property-set 'autoAccidentals auto-accs)
+                  (make-property-set 'autoCautionaries auto-cauts))))

    context))
 
 (define-public (set-accidental-style style . rest)
    context))
 
 (define-public (set-accidental-style style . rest)


@@ -1428,163 +1620,163 @@ argument, e.g. @code{'Staff} or @code{'Voice}.  The context defaults
 to @code{Staff}, except for piano styles, which use @code{GrandStaff}
 as a context."
   (let ((context (if (pair? rest)
 to @code{Staff}, except for piano styles, which use @code{GrandStaff}
 as a context."
   (let ((context (if (pair? rest)

-                    (car rest) 'Staff))
-       (pcontext (if (pair? rest)
-                     (car rest) 'GrandStaff)))
+                     (car rest) 'Staff))
+        (pcontext (if (pair? rest)
+                      (car rest) 'GrandStaff)))

     (cond
     (cond

-      ;; accidentals as they were common in the 18th century.
-      ((equal? style 'default)
-       (set-accidentals-properties #t
-                                  `(Staff ,(make-accidental-rule 'same-octave 0))
-                                  '()
-                                  context))
-      ;; accidentals from one voice do NOT get canceled in other voices
-      ((equal? style 'voice)
-       (set-accidentals-properties #t
-                                  `(Voice ,(make-accidental-rule 'same-octave 0))
-                                  '()
-                                  context))
-      ;; accidentals as suggested by Kurt Stone, Music Notation in the 20th century.
-      ;; This includes all the default accidentals, but accidentals also needs canceling
-      ;; in other octaves and in the next measure.
-      ((equal? style 'modern)
-       (set-accidentals-properties #f
-                                  `(Staff ,(make-accidental-rule 'same-octave 0)
-                                          ,(make-accidental-rule 'any-octave 0)
-                                          ,(make-accidental-rule 'same-octave 1))
-                                  '()
-                                  context))
-      ;; the accidentals that Stone adds to the old standard as cautionaries
-      ((equal? style 'modern-cautionary)
-       (set-accidentals-properties #f
-                                  `(Staff ,(make-accidental-rule 'same-octave 0))
-                                  `(Staff ,(make-accidental-rule 'any-octave 0)
-                                          ,(make-accidental-rule 'same-octave 1))
-                                  context))
-      ;; same as modern, but accidentals different from the key signature are always
-      ;; typeset - unless they directly follow a note of the same pitch.
-      ((equal? style 'neo-modern)
-       (set-accidentals-properties #f
-                                  `(Staff ,(make-accidental-rule 'same-octave 0)
-                                          ,(make-accidental-rule 'any-octave 0)
-                                          ,(make-accidental-rule 'same-octave 1)
-                                          ,neo-modern-accidental-rule)
-                                  '()
-                                  context))
-      ((equal? style 'neo-modern-cautionary)
-       (set-accidentals-properties #f
-                                  `(Staff ,(make-accidental-rule 'same-octave 0))
-                                  `(Staff ,(make-accidental-rule 'any-octave 0)
-                                          ,(make-accidental-rule 'same-octave 1)
-                                          ,neo-modern-accidental-rule)
-                                  context))
-      ((equal? style 'neo-modern-voice)
-       (set-accidentals-properties #f
-                                  `(Voice ,(make-accidental-rule 'same-octave 0)
-                                          ,(make-accidental-rule 'any-octave 0)
-                                          ,(make-accidental-rule 'same-octave 1)
-                                          ,neo-modern-accidental-rule
-                                    Staff ,(make-accidental-rule 'same-octave 0)
-                                          ,(make-accidental-rule 'any-octave 0)
-                                          ,(make-accidental-rule 'same-octave 1)
-                                     ,neo-modern-accidental-rule)
-                                  '()
-                                  context))
-      ((equal? style 'neo-modern-voice-cautionary)
-       (set-accidentals-properties #f
-                                  `(Voice ,(make-accidental-rule 'same-octave 0))
-                                  `(Voice ,(make-accidental-rule 'any-octave 0)
-                                          ,(make-accidental-rule 'same-octave 1)
-                                          ,neo-modern-accidental-rule
-                                    Staff ,(make-accidental-rule 'same-octave 0)
-                                          ,(make-accidental-rule 'any-octave 0)
-                                          ,(make-accidental-rule 'same-octave 1)
-                                          ,neo-modern-accidental-rule)
-                                  context))
-      ;; Accidentals as they were common in dodecaphonic music with no tonality.
-      ;; Each note gets one accidental.
-      ((equal? style 'dodecaphonic)
-       (set-accidentals-properties #f
-                                  `(Staff ,(lambda (c p bn mp) '(#f . #t)))
-                                  '()
-                                  context))
-      ;; Multivoice accidentals to be read both by musicians playing one voice
-      ;; and musicians playing all voices.
-      ;; Accidentals are typeset for each voice, but they ARE canceled across voices.
-      ((equal? style 'modern-voice)
-       (set-accidentals-properties  #f
-                                   `(Voice ,(make-accidental-rule 'same-octave 0)
-                                           ,(make-accidental-rule 'any-octave 0)
-                                           ,(make-accidental-rule 'same-octave 1)
-                                     Staff ,(make-accidental-rule 'same-octave 0)
-                                           ,(make-accidental-rule 'any-octave 0)
-                                           ,(make-accidental-rule 'same-octave 1))
-                                   '()
-                                   context))
-      ;; same as modernVoiceAccidental eccept that all special accidentals are typeset
-      ;; as cautionaries
-      ((equal? style 'modern-voice-cautionary)
-       (set-accidentals-properties #f
-                                  `(Voice ,(make-accidental-rule 'same-octave 0))
-                                  `(Voice ,(make-accidental-rule 'any-octave 0)
-                                          ,(make-accidental-rule 'same-octave 1)
-                                    Staff ,(make-accidental-rule 'same-octave 0)
-                                          ,(make-accidental-rule 'any-octave 0)
-                                          ,(make-accidental-rule 'same-octave 1))
-                                  context))
-      ;; stone's suggestions for accidentals on grand staff.
-      ;; Accidentals are canceled across the staves in the same grand staff as well
-      ((equal? style 'piano)
-       (set-accidentals-properties #f
-                                  `(Staff ,(make-accidental-rule 'same-octave 0)
-                                          ,(make-accidental-rule 'any-octave 0)
-                                          ,(make-accidental-rule 'same-octave 1)
-                                    GrandStaff
-                                          ,(make-accidental-rule 'any-octave 0)
-                                          ,(make-accidental-rule 'same-octave 1))
-                                  '()
-                                  pcontext))
-      ((equal? style 'piano-cautionary)
-       (set-accidentals-properties #f
-                                  `(Staff ,(make-accidental-rule 'same-octave 0))
-                                  `(Staff ,(make-accidental-rule 'any-octave 0)
-                                          ,(make-accidental-rule 'same-octave 1)
-                                    GrandStaff
-                                          ,(make-accidental-rule 'any-octave 0)
-                                          ,(make-accidental-rule 'same-octave 1))
-                                  pcontext))
-
-      ;; same as modern, but cautionary accidentals are printed for all sharp or flat
-      ;; tones specified by the key signature.
-       ((equal? style 'teaching)
-       (set-accidentals-properties #f
-                                   `(Staff ,(make-accidental-rule 'same-octave 0))
-                                   `(Staff ,(make-accidental-rule 'same-octave 1)
-                                          ,teaching-accidental-rule)
-                                  context))
-
-      ;; do not set localKeySignature when a note alterated differently from
-      ;; localKeySignature is found.
-      ;; Causes accidentals to be printed at every note instead of
-      ;; remembered for the duration of a measure.
-      ;; accidentals not being remembered, causing accidentals always to
-      ;; be typeset relative to the time signature
-      ((equal? style 'forget)
-       (set-accidentals-properties '()
-                                  `(Staff ,(make-accidental-rule 'same-octave -1))
-                                  '()
-                                  context))
-      ;; Do not reset the key at the start of a measure.  Accidentals will be
-      ;; printed only once and are in effect until overridden, possibly many
-      ;; measures later.
-      ((equal? style 'no-reset)
-       (set-accidentals-properties '()
-                                  `(Staff ,(make-accidental-rule 'same-octave #t))
-                                  '()
-                                  context))
-      (else
-       (ly:warning (_ "unknown accidental style: ~S") style)
-       (make-sequential-music '())))))
+     ;; accidentals as they were common in the 18th century.
+     ((equal? style 'default)
+      (set-accidentals-properties #t
+                                  `(Staff ,(make-accidental-rule 'same-octave 0))
+                                  '()
+                                  context))
+     ;; accidentals from one voice do NOT get canceled in other voices
+     ((equal? style 'voice)
+      (set-accidentals-properties #t
+                                  `(Voice ,(make-accidental-rule 'same-octave 0))
+                                  '()
+                                  context))
+     ;; accidentals as suggested by Kurt Stone, Music Notation in the 20th century.
+     ;; This includes all the default accidentals, but accidentals also needs canceling
+     ;; in other octaves and in the next measure.
+     ((equal? style 'modern)
+      (set-accidentals-properties #f
+                                  `(Staff ,(make-accidental-rule 'same-octave 0)
+                                          ,(make-accidental-rule 'any-octave 0)
+                                          ,(make-accidental-rule 'same-octave 1))
+                                  '()
+                                  context))
+     ;; the accidentals that Stone adds to the old standard as cautionaries
+     ((equal? style 'modern-cautionary)
+      (set-accidentals-properties #f
+                                  `(Staff ,(make-accidental-rule 'same-octave 0))
+                                  `(Staff ,(make-accidental-rule 'any-octave 0)
+                                          ,(make-accidental-rule 'same-octave 1))
+                                  context))
+     ;; same as modern, but accidentals different from the key signature are always
+     ;; typeset - unless they directly follow a note of the same pitch.
+     ((equal? style 'neo-modern)
+      (set-accidentals-properties #f
+                                  `(Staff ,(make-accidental-rule 'same-octave 0)
+                                          ,(make-accidental-rule 'any-octave 0)
+                                          ,(make-accidental-rule 'same-octave 1)
+                                          ,neo-modern-accidental-rule)
+                                  '()
+                                  context))
+     ((equal? style 'neo-modern-cautionary)
+      (set-accidentals-properties #f
+                                  `(Staff ,(make-accidental-rule 'same-octave 0))
+                                  `(Staff ,(make-accidental-rule 'any-octave 0)
+                                          ,(make-accidental-rule 'same-octave 1)
+                                          ,neo-modern-accidental-rule)
+                                  context))
+     ((equal? style 'neo-modern-voice)
+      (set-accidentals-properties #f
+                                  `(Voice ,(make-accidental-rule 'same-octave 0)
+                                          ,(make-accidental-rule 'any-octave 0)
+                                          ,(make-accidental-rule 'same-octave 1)
+                                          ,neo-modern-accidental-rule
+                                          Staff ,(make-accidental-rule 'same-octave 0)
+                                          ,(make-accidental-rule 'any-octave 0)
+                                          ,(make-accidental-rule 'same-octave 1)
+                                          ,neo-modern-accidental-rule)
+                                  '()
+                                  context))
+     ((equal? style 'neo-modern-voice-cautionary)
+      (set-accidentals-properties #f
+                                  `(Voice ,(make-accidental-rule 'same-octave 0))
+                                  `(Voice ,(make-accidental-rule 'any-octave 0)
+                                          ,(make-accidental-rule 'same-octave 1)
+                                          ,neo-modern-accidental-rule
+                                          Staff ,(make-accidental-rule 'same-octave 0)
+                                          ,(make-accidental-rule 'any-octave 0)
+                                          ,(make-accidental-rule 'same-octave 1)
+                                          ,neo-modern-accidental-rule)
+                                  context))
+     ;; Accidentals as they were common in dodecaphonic music with no tonality.
+     ;; Each note gets one accidental.
+     ((equal? style 'dodecaphonic)
+      (set-accidentals-properties #f
+                                  `(Staff ,(lambda (c p bn mp) '(#f . #t)))
+                                  '()
+                                  context))
+     ;; Multivoice accidentals to be read both by musicians playing one voice
+     ;; and musicians playing all voices.
+     ;; Accidentals are typeset for each voice, but they ARE canceled across voices.
+     ((equal? style 'modern-voice)
+      (set-accidentals-properties  #f
+                                   `(Voice ,(make-accidental-rule 'same-octave 0)
+                                           ,(make-accidental-rule 'any-octave 0)
+                                           ,(make-accidental-rule 'same-octave 1)
+                                           Staff ,(make-accidental-rule 'same-octave 0)
+                                           ,(make-accidental-rule 'any-octave 0)
+                                           ,(make-accidental-rule 'same-octave 1))
+                                   '()
+                                   context))
+     ;; same as modernVoiceAccidental eccept that all special accidentals are typeset
+     ;; as cautionaries
+     ((equal? style 'modern-voice-cautionary)
+      (set-accidentals-properties #f
+                                  `(Voice ,(make-accidental-rule 'same-octave 0))
+                                  `(Voice ,(make-accidental-rule 'any-octave 0)
+                                          ,(make-accidental-rule 'same-octave 1)
+                                          Staff ,(make-accidental-rule 'same-octave 0)
+                                          ,(make-accidental-rule 'any-octave 0)
+                                          ,(make-accidental-rule 'same-octave 1))
+                                  context))
+     ;; stone's suggestions for accidentals on grand staff.
+     ;; Accidentals are canceled across the staves in the same grand staff as well
+     ((equal? style 'piano)
+      (set-accidentals-properties #f
+                                  `(Staff ,(make-accidental-rule 'same-octave 0)
+                                          ,(make-accidental-rule 'any-octave 0)
+                                          ,(make-accidental-rule 'same-octave 1)
+                                          GrandStaff
+                                          ,(make-accidental-rule 'any-octave 0)
+                                          ,(make-accidental-rule 'same-octave 1))
+                                  '()
+                                  pcontext))
+     ((equal? style 'piano-cautionary)
+      (set-accidentals-properties #f
+                                  `(Staff ,(make-accidental-rule 'same-octave 0))
+                                  `(Staff ,(make-accidental-rule 'any-octave 0)
+                                          ,(make-accidental-rule 'same-octave 1)
+                                          GrandStaff
+                                          ,(make-accidental-rule 'any-octave 0)
+                                          ,(make-accidental-rule 'same-octave 1))
+                                  pcontext))
+
+     ;; same as modern, but cautionary accidentals are printed for all sharp or flat
+     ;; tones specified by the key signature.
+     ((equal? style 'teaching)
+      (set-accidentals-properties #f
+                                  `(Staff ,(make-accidental-rule 'same-octave 0))
+                                  `(Staff ,(make-accidental-rule 'same-octave 1)
+                                          ,teaching-accidental-rule)
+                                  context))
+
+     ;; do not set localKeySignature when a note alterated differently from
+     ;; localKeySignature is found.
+     ;; Causes accidentals to be printed at every note instead of
+     ;; remembered for the duration of a measure.
+     ;; accidentals not being remembered, causing accidentals always to
+     ;; be typeset relative to the time signature
+     ((equal? style 'forget)
+      (set-accidentals-properties '()
+                                  `(Staff ,(make-accidental-rule 'same-octave -1))
+                                  '()
+                                  context))
+     ;; Do not reset the key at the start of a measure.  Accidentals will be
+     ;; printed only once and are in effect until overridden, possibly many
+     ;; measures later.
+     ((equal? style 'no-reset)
+      (set-accidentals-properties '()
+                                  `(Staff ,(make-accidental-rule 'same-octave #t))
+                                  '()
+                                  context))
+     (else
+      (ly:warning (_ "unknown accidental style: ~S") style)
+      (make-sequential-music '())))))

 
 (define-public (invalidate-alterations context)
   "Invalidate alterations in @var{context}.
 
 (define-public (invalidate-alterations context)
   "Invalidate alterations in @var{context}.


@@ -1598,31 +1790,31 @@ to force a repetition of accidentals.
 Entries that conform with the current key signature are not invalidated."
   (let* ((keysig (ly:context-property context 'keySignature)))
     (set! (ly:context-property context 'localKeySignature)
 Entries that conform with the current key signature are not invalidated."
   (let* ((keysig (ly:context-property context 'keySignature)))
     (set! (ly:context-property context 'localKeySignature)

-         (map-in-order
-          (lambda (entry)
-            (let* ((localalt (key-entry-alteration entry)))
-              (if (or (accidental-invalid? localalt)
-                      (not (key-entry-bar-number entry))
-                      (= localalt
-                         (key-entry-alteration
-                          (find-pitch-entry
-                           keysig
-                           (ly:make-pitch (key-entry-octave entry)
-                                          (key-entry-notename entry)
-                                          0)
-                           #t #t))))
-                  entry
-                  (cons (car entry) (cons 'clef (cddr entry))))))
-          (ly:context-property context 'localKeySignature)))))
+          (map-in-order
+           (lambda (entry)
+             (let* ((localalt (key-entry-alteration entry)))
+               (if (or (accidental-invalid? localalt)
+                       (not (key-entry-bar-number entry))
+                       (= localalt
+                          (key-entry-alteration
+                           (find-pitch-entry
+                            keysig
+                            (ly:make-pitch (key-entry-octave entry)
+                                           (key-entry-notename entry)
+                                           0)
+                            #t #t))))
+                   entry
+                   (cons (car entry) (cons 'clef (cddr entry))))))
+           (ly:context-property context 'localKeySignature)))))

 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 (define-public (skip-of-length mus)
   "Create a skip of exactly the same length as @var{mus}."
   (let* ((skip
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 (define-public (skip-of-length mus)
   "Create a skip of exactly the same length as @var{mus}."
   (let* ((skip

-         (make-music
-          'SkipEvent
-          'duration (ly:make-duration 0 0))))
+          (make-music
+           'SkipEvent
+           'duration (ly:make-duration 0 0))))

 
     (make-event-chord (list (ly:music-compress skip (ly:music-length mus))))))
 
 
     (make-event-chord (list (ly:music-compress skip (ly:music-length mus))))))
 


@@ -1630,62 +1822,66 @@ Entries that conform with the current key signature are not invalidated."
   "Create a multi-measure rest of exactly the same length as @var{mus}."
 
   (let* ((skip
   "Create a multi-measure rest of exactly the same length as @var{mus}."
 
   (let* ((skip

-         (make-multi-measure-rest
-          (ly:make-duration 0 0) '())))
+          (make-multi-measure-rest
+           (ly:make-duration 0 0) '())))

     (ly:music-compress skip (ly:music-length mus))
     skip))
 
 (define-public (pitch-of-note event-chord)
   (let ((evs (filter (lambda (x)
     (ly:music-compress skip (ly:music-length mus))
     skip))
 
 (define-public (pitch-of-note event-chord)
   (let ((evs (filter (lambda (x)

-                      (music-has-type x 'note-event))
-                    (ly:music-property event-chord 'elements))))
+                       (music-has-type x 'note-event))
+                     (ly:music-property event-chord 'elements))))

 
     (and (pair? evs)
 
     (and (pair? evs)

-        (ly:music-property (car evs) 'pitch))))
+         (ly:music-property (car evs) 'pitch))))

 
 (define-public (duration-of-note event-chord)
   (cond
    ((pair? event-chord)
     (or (duration-of-note (car event-chord))
 
 (define-public (duration-of-note event-chord)
   (cond
    ((pair? event-chord)
     (or (duration-of-note (car event-chord))

-       (duration-of-note (cdr event-chord))))
+        (duration-of-note (cdr event-chord))))

    ((ly:music? event-chord)
     (let ((dur (ly:music-property event-chord 'duration)))
       (if (ly:duration? dur)
    ((ly:music? event-chord)
     (let ((dur (ly:music-property event-chord 'duration)))
       (if (ly:duration? dur)

-         dur
-         (duration-of-note (ly:music-property event-chord 'elements)))))
+          dur
+          (duration-of-note (ly:music-property event-chord 'elements)))))

    (else #f)))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 (define-public (map-some-music map? music)
   "Walk through @var{music}, transform all elements calling @var{map?}
    (else #f)))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 (define-public (map-some-music map? music)
   "Walk through @var{music}, transform all elements calling @var{map?}

-and only recurse if this returns @code{#f}."
+and only recurse if this returns @code{#f}.  @code{elements} or
+@code{articulations} that are not music expressions are discarded:
+this allows some amount of filtering.
+
+@code{map-some-music} may overwrite the original @var{music}."

   (let loop ((music music))
     (or (map? music)
   (let loop ((music music))
     (or (map? music)

-       (let ((elt (ly:music-property music 'element))
-             (elts (ly:music-property music 'elements))
-             (arts (ly:music-property music 'articulations)))
-         (if (ly:music? elt)
-             (set! (ly:music-property music 'element)
-                   (loop elt)))
-         (if (pair? elts)
-             (set! (ly:music-property music 'elements)
-                   (map loop elts)))
-         (if (pair? arts)
-             (set! (ly:music-property music 'articulations)
-                   (map loop arts)))
-         music))))
+        (let ((elt (ly:music-property music 'element))
+              (elts (ly:music-property music 'elements))
+              (arts (ly:music-property music 'articulations)))
+          (if (ly:music? elt)
+              (set! (ly:music-property music 'element)
+                    (loop elt)))
+          (if (pair? elts)
+              (set! (ly:music-property music 'elements)
+                    (filter! ly:music? (map! loop elts))))
+          (if (pair? arts)
+              (set! (ly:music-property music 'articulations)
+                    (filter! ly:music? (map! loop arts))))
+          music))))

 
 (define-public (for-some-music stop? music)
   "Walk through @var{music}, process all elements calling @var{stop?}
 and only recurse if this returns @code{#f}."
   (let loop ((music music))
     (if (not (stop? music))
 
 (define-public (for-some-music stop? music)
   "Walk through @var{music}, process all elements calling @var{stop?}
 and only recurse if this returns @code{#f}."
   (let loop ((music music))
     (if (not (stop? music))

-       (let ((elt (ly:music-property music 'element)))
-         (if (ly:music? elt)
-             (loop elt))
-         (for-each loop (ly:music-property music 'elements))
-         (for-each loop (ly:music-property music 'articulations))))))
+        (let ((elt (ly:music-property music 'element)))
+          (if (ly:music? elt)
+              (loop elt))
+          (for-each loop (ly:music-property music 'elements))
+          (for-each loop (ly:music-property music 'articulations))))))

 
 (define-public (fold-some-music pred? proc init music)
   "This works recursively on music like @code{fold} does on a list,
 
 (define-public (fold-some-music pred? proc init music)
   "This works recursively on music like @code{fold} does on a list,


@@ -1697,15 +1893,15 @@ and no recursion happens.
 The top @var{music} is processed using @var{init} for @samp{previous}."
   (let loop ((music music) (previous init))
     (if (pred? music)
 The top @var{music} is processed using @var{init} for @samp{previous}."
   (let loop ((music music) (previous init))
     (if (pred? music)

-       (proc music previous)
-       (fold loop
-             (fold loop
-                   (let ((elt (ly:music-property music 'element)))
-                     (if (null? elt)
-                         previous
-                         (loop elt previous)))
-                   (ly:music-property music 'elements))
-             (ly:music-property music 'articulations)))))
+        (proc music previous)
+        (fold loop
+              (fold loop
+                    (let ((elt (ly:music-property music 'element)))
+                      (if (null? elt)
+                          previous
+                          (loop elt previous)))
+                    (ly:music-property music 'elements))
+              (ly:music-property music 'articulations)))))

 
 (define-public (extract-music music pred?)
   "Return a flat list of all music matching @var{pred?} inside of
 
 (define-public (extract-music music pred?)
   "Return a flat list of all music matching @var{pred?} inside of


@@ -1730,7 +1926,7 @@ recursing into matches themselves."
    music
    (if (cheap-list? type)
        (lambda (m)
    music
    (if (cheap-list? type)
        (lambda (m)

-        (any (lambda (t) (music-is-of-type? m t)) type))
+         (any (lambda (t) (music-is-of-type? m t)) type))

        (lambda (m) (music-is-of-type? m type)))))
 
 (define*-public (event-chord-wrap! music #:optional parser)
        (lambda (m) (music-is-of-type? m type)))))
 
 (define*-public (event-chord-wrap! music #:optional parser)


@@ -1742,44 +1938,151 @@ yourself."
   (map-some-music
    (lambda (m)
      (cond ((music-is-of-type? m 'event-chord)
   (map-some-music
    (lambda (m)
      (cond ((music-is-of-type? m 'event-chord)

-           (if (pair? (ly:music-property m 'articulations))
-               (begin
-                 (set! (ly:music-property m 'elements)
-                       (append (ly:music-property m 'elements)
-                               (ly:music-property m 'articulations)))
-                 (set! (ly:music-property m 'articulations) '())))
-           m)
-          ((music-is-of-type? m 'rhythmic-event)
-           (let ((arts (ly:music-property m 'articulations)))
-             (if (pair? arts)
-                 (set! (ly:music-property m 'articulations) '()))
-             (make-event-chord (cons m arts))))
-          (else #f)))
+            (if (pair? (ly:music-property m 'articulations))
+                (begin
+                  (set! (ly:music-property m 'elements)
+                        (append (ly:music-property m 'elements)
+                                (ly:music-property m 'articulations)))
+                  (set! (ly:music-property m 'articulations) '())))
+            m)
+           ((music-is-of-type? m 'rhythmic-event)
+            (let ((arts (ly:music-property m 'articulations)))
+              (if (pair? arts)
+                  (set! (ly:music-property m 'articulations) '()))
+              (make-event-chord (cons m arts))))
+           (else #f)))

    (if parser
        (expand-repeat-chords!
    (if parser
        (expand-repeat-chords!

-       (cons 'rhythmic-event
-             (ly:parser-lookup parser '$chord-repeat-events))
-       music)
+        (cons 'rhythmic-event
+              (ly:parser-lookup parser '$chord-repeat-events))
+        music)

        music)))
 
 (define-public (event-chord-notes event-chord)
   "Return a list of all notes from @var{event-chord}."
   (filter
        music)))
 
 (define-public (event-chord-notes event-chord)
   "Return a list of all notes from @var{event-chord}."
   (filter

-    (lambda (m) (eq? 'NoteEvent (ly:music-property m 'name)))
-    (ly:music-property event-chord 'elements)))
+   (lambda (m) (eq? 'NoteEvent (ly:music-property m 'name)))
+   (ly:music-property event-chord 'elements)))

 
 (define-public (event-chord-pitches event-chord)
   "Return a list of all pitches from @var{event-chord}."
   (map (lambda (x) (ly:music-property x 'pitch))
        (event-chord-notes event-chord)))
 
 
 (define-public (event-chord-pitches event-chord)
   "Return a list of all pitches from @var{event-chord}."
   (map (lambda (x) (ly:music-property x 'pitch))
        (event-chord-notes event-chord)))
 

-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; The following functions are all associated with the crossStaff
-;  function
+(define-public (event-chord-reduce music)
+  "Reduces event chords in @var{music} to their first note event,
+retaining only the chord articulations.  Returns the modified music."
+  (map-some-music
+   (lambda (m)
+     (and (music-is-of-type? m 'event-chord)
+          (let*-values (((notes arts) (partition
+                                       (lambda (mus)
+                                         (music-is-of-type? mus 'rhythmic-event))
+                                       (ly:music-property m 'elements)))
+                        ((dur) (ly:music-property m 'duration))
+                        ((full-arts) (append arts
+                                             (ly:music-property m 'articulations)))
+                        ((first-note) (and (pair? notes) (car notes))))
+            (cond (first-note
+                   (set! (ly:music-property first-note 'articulations)
+                         full-arts)
+                   first-note)
+                  ((ly:duration? dur)
+                   ;; A repeat chord. Produce an unpitched note.
+                   (make-music 'NoteEvent
+                               'duration dur
+                               'articulations full-arts))
+                  (else
+                   (ly:music-error m (_ "Missing duration"))
+                   (make-music 'NoteEvent
+                               'duration (ly:make-duration 2 0 0)
+                               'articulations full-arts))))))
+   music))
+
+
+(defmacro-public make-relative (variables reference music)
+  "The list of pitch or music variables in @var{variables} is used as
+a sequence for creating relativable music from @var{music}.
+
+When the constructed music is used outside of @code{\\relative}, it
+just reflects plugging in the @var{variables} into @var{music}.
+
+The action inside of @code{\\relative}, however, is determined by
+first relativizing the surrogate @var{reference} with the variables
+plugged in and then using the variables relativized as a side effect
+of relativizing @var{reference} for evaluating @var{music}.
+
+Since pitches don't have the object identity required for tracing the
+effect of the reference call, they are replaced @emph{only} for the
+purpose of evaluating @var{reference} with simple pitched note events.
+
+The surrogate @var{reference} expression has to be written with that
+in mind.  In addition, it must @emph{not} contain @emph{copies} of
+music that is supposed to be relativized but rather the
+@emph{originals}.  This @emph{includes} the pitch expressions.  As a
+rule, inside of @code{#@{@dots{}#@}} variables must @emph{only} be
+introduced using @code{#}, never via the copying construct @code{$}.
+The reference expression will usually just be a sequential or chord
+expression naming all variables in sequence, implying that following
+music will be relativized according to the resulting pitch of the last
+or first variable, respectively.
+
+Since the usual purpose is to create more complex music from general
+arguments and since music expression parts must not occur more than
+once, one @emph{does} generally need to use copying operators in the
+@emph{replacement} expression @var{music} when using an argument more
+than once there.  Using an argument more than once in @var{reference},
+in contrast, does not make sense.
+
+There is another fine point to mind: @var{music} must @emph{only}
+contain freshly constructed elements or copied constructs.  This will
+be the case anyway for regular LilyPond code inside of
+@code{#@{@dots{}#@}}, but any other elements (apart from the
+@var{variables} themselves which are already copied) must be created
+or copied as well.
+
+The reason is that it is usually permitted to change music in-place as
+long as one does a @var{ly:music-deep-copy} on it, and such a copy of
+the whole resulting expression will @emph{not} be able to copy
+variables/values inside of closures where the information for
+relativization is being stored.
+"
+
+  ;; pitch and music generator might be stored instead in music
+  ;; properties, and it might make sense to create a music type of its
+  ;; own for this kind of construct rather than using
+  ;; RelativeOctaveMusic
+  (define ((make-relative::to-relative-callback variables music-call ref-call)
+           music pitch)
+    (let* ((ref-vars (map (lambda (v)
+                            (if (ly:pitch? v)
+                                (make-music 'NoteEvent 'pitch v)
+                                (ly:music-deep-copy v)))
+                          variables))
+           (after-pitch (ly:make-music-relative! (apply ref-call ref-vars) pitch))
+           (actual-vars (map (lambda (v r)
+                               (if (ly:pitch? v)
+                                   (ly:music-property r 'pitch)
+                                   r))
+                             variables ref-vars))
+           (rel-music (apply music-call actual-vars)))
+      (set! (ly:music-property music 'element) rel-music)
+      after-pitch))
+  `(make-music 'RelativeOctaveMusic
+               'to-relative-callback
+               (,make-relative::to-relative-callback
+                (list ,@variables)
+                (lambda ,variables ,music)
+                (lambda ,variables ,reference))
+               'element ,music))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; The following functions are all associated with the crossStaff
+;;  function

 
 (define (close-enough? x y)
   "Values are close enough to ignore the difference"
 
 (define (close-enough? x y)
   "Values are close enough to ignore the difference"

-   (< (abs (- x y)) 0.0001))
+  (< (abs (- x y)) 0.0001))

 
 (define (extent-combine extents)
   "Combine a list of extents"
 
 (define (extent-combine extents)
   "Combine a list of extents"


@@ -1789,51 +2092,51 @@ yourself."
 
 (define ((stem-connectable? ref root) stem)
   "Check if the stem is connectable to the root"
 
 (define ((stem-connectable? ref root) stem)
   "Check if the stem is connectable to the root"

-  ; The root is always connectable to itself
+  ;; The root is always connectable to itself

   (or (eq? root stem)
       (and
   (or (eq? root stem)
       (and

-      ; Horizontal positions of the stems must be almost the same
-        (close-enough? (car (ly:grob-extent root ref X))
-          (car (ly:grob-extent stem ref X)))
-        ; The stem must be in the direction away from the root's notehead
-        (positive? (* (ly:grob-property root 'direction)
+       ;; Horizontal positions of the stems must be almost the same
+       (close-enough? (car (ly:grob-extent root ref X))
+                      (car (ly:grob-extent stem ref X)))
+       ;; The stem must be in the direction away from the root's notehead
+       (positive? (* (ly:grob-property root 'direction)

                      (- (car (ly:grob-extent stem ref Y))
                      (- (car (ly:grob-extent stem ref Y))

-                       (car (ly:grob-extent root ref Y))))))))
+                        (car (ly:grob-extent root ref Y))))))))

 
 (define (stem-span-stencil span)
   "Connect stems if we have at least one stem connectable to the root"
   (let* ((system (ly:grob-system span))
 
 (define (stem-span-stencil span)
   "Connect stems if we have at least one stem connectable to the root"
   (let* ((system (ly:grob-system span))

-          (root (ly:grob-parent span X))
-          (stems (filter (stem-connectable? system root)
-                         (ly:grob-object span 'stems))))
-     (if (<= 2 (length stems))
-         (let* ((yextents (map (lambda (st)
-                                 (ly:grob-extent st system Y)) stems))
-                (yextent (extent-combine yextents))
-                (layout (ly:grob-layout root))
-                (blot (ly:output-def-lookup layout 'blot-diameter)))
-           ; Hide spanned stems
-           (map (lambda (st)
-                  (set! (ly:grob-property st 'transparent) #t))
-             stems)
-           ; Draw a nice looking stem with rounded corners
-           (ly:round-filled-box (ly:grob-extent root root X) yextent blot))
-         ; Nothing to connect, don't draw the span
-         #f)))
+         (root (ly:grob-parent span X))
+         (stems (filter (stem-connectable? system root)
+                        (ly:grob-object span 'stems))))
+    (if (<= 2 (length stems))
+        (let* ((yextents (map (lambda (st)
+                                (ly:grob-extent st system Y)) stems))
+               (yextent (extent-combine yextents))
+               (layout (ly:grob-layout root))
+               (blot (ly:output-def-lookup layout 'blot-diameter)))
+          ;; Hide spanned stems
+          (for-each (lambda (st)
+                      (set! (ly:grob-property st 'stencil) #f))
+                    stems)
+          ;; Draw a nice looking stem with rounded corners
+          (ly:round-filled-box (ly:grob-extent root root X) yextent blot))
+        ;; Nothing to connect, don't draw the span
+        #f)))

 
 (define ((make-stem-span! stems trans) root)
   "Create a stem span as a child of the cross-staff stem (the root)"
   (let ((span (ly:engraver-make-grob trans 'Stem '())))
     (ly:grob-set-parent! span X root)
     (set! (ly:grob-object span 'stems) stems)
 
 (define ((make-stem-span! stems trans) root)
   "Create a stem span as a child of the cross-staff stem (the root)"
   (let ((span (ly:engraver-make-grob trans 'Stem '())))
     (ly:grob-set-parent! span X root)
     (set! (ly:grob-object span 'stems) stems)

-    ; Suppress positioning, the stem code is confused by this weird stem
+    ;; Suppress positioning, the stem code is confused by this weird stem

     (set! (ly:grob-property span 'X-offset) 0)
     (set! (ly:grob-property span 'stencil) stem-span-stencil)))
 
 (define-public (cross-staff-connect stem)
   "Set cross-staff property of the stem to this function to connect it to
 other stems automatically"
     (set! (ly:grob-property span 'X-offset) 0)
     (set! (ly:grob-property span 'stencil) stem-span-stencil)))
 
 (define-public (cross-staff-connect stem)
   "Set cross-staff property of the stem to this function to connect it to
 other stems automatically"

-   #t)
+  #t)

 
 (define (stem-is-root? stem)
   "Check if automatic connecting of the stem was requested.  Stems connected
 
 (define (stem-is-root? stem)
   "Check if automatic connecting of the stem was requested.  Stems connected


@@ -1843,24 +2146,24 @@ other stems just because of that."
 
 (define (make-stem-spans! ctx stems trans)
   "Create stem spans for cross-staff stems"
 
 (define (make-stem-spans! ctx stems trans)
   "Create stem spans for cross-staff stems"

-  ; Cannot do extensive checks here, just make sure there are at least
-  ; two stems at this musical moment
+  ;; Cannot do extensive checks here, just make sure there are at least
+  ;; two stems at this musical moment

   (if (<= 2 (length stems))
   (if (<= 2 (length stems))

-    (let ((roots (filter stem-is-root? stems)))
-    (map (make-stem-span! stems trans) roots))))
+      (let ((roots (filter stem-is-root? stems)))
+        (for-each (make-stem-span! stems trans) roots))))

 
 (define-public (Span_stem_engraver ctx)
   "Connect cross-staff stems to the stems above in the system"
   (let ((stems '()))
     (make-engraver
 
 (define-public (Span_stem_engraver ctx)
   "Connect cross-staff stems to the stems above in the system"
   (let ((stems '()))
     (make-engraver

-      ; Record all stems for the given moment
-      (acknowledgers
-        ((stem-interface trans grob source)
-        (set! stems (cons grob stems))))
-      ; Process stems and reset the stem list to empty
-      ((process-acknowledged trans)
-        (make-stem-spans! ctx stems trans)
-        (set! stems '())))))
+     ;; Record all stems for the given moment
+     (acknowledgers
+      ((stem-interface trans grob source)
+       (set! stems (cons grob stems))))
+     ;; Process stems and reset the stem list to empty
+     ((process-acknowledged trans)
+      (make-stem-spans! ctx stems trans)
+      (set! stems '())))))

 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; The following is used by the alterBroken function.
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; The following is used by the alterBroken function.


@@ -1871,13 +2174,166 @@ of list @var{arg}."
   (let* ((orig (ly:grob-original grob))
          (siblings (ly:spanner-broken-into orig)))
 
   (let* ((orig (ly:grob-original grob))
          (siblings (ly:spanner-broken-into orig)))
 

-   (define (helper sibs arg)
-     (if (null? arg)
-         arg
-         (if (eq? (car sibs) grob)
-             (car arg)
-             (helper (cdr sibs) (cdr arg)))))
+    (define (helper sibs arg)
+      (if (null? arg)
+          arg
+          (if (eq? (car sibs) grob)
+              (car arg)
+              (helper (cdr sibs) (cdr arg)))))
+
+    (if (>= (length siblings) 2)
+        (helper siblings arg)
+        (car arg))))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; measure counter
+
+(define (measure-counter-stencil grob)
+  "Print a number for a measure count.  The number is centered using
+the extents of @code{BreakAlignment} grobs associated with
+@code{NonMusicalPaperColumn} grobs.  In the case of an unbroken measure, these
+columns are the left and right bounds of a @code{MeasureCounter} spanner.
+Broken measures are numbered in parentheses."
+  (let* ((orig (ly:grob-original grob))
+         (siblings (ly:spanner-broken-into orig)) ; have we been split?
+         (bounds (ly:grob-array->list (ly:grob-object grob 'columns)))
+         (refp (ly:grob-system grob))
+         ;; we use the first and/or last NonMusicalPaperColumn grob(s) of
+         ;; a system in the event that a MeasureCounter spanner is broken
+         (all-cols (ly:grob-array->list (ly:grob-object refp 'columns)))
+         (all-cols
+          (filter
+           (lambda (col) (eq? #t (ly:grob-property col 'non-musical)))
+           all-cols))
+         (left-bound
+          (if (or (null? siblings) ; spanner is unbroken
+                  (eq? grob (car siblings))) ; or the first piece
+              (car bounds)
+              (car all-cols)))
+         (right-bound
+          (if (or (null? siblings)
+                  (eq? grob (car (reverse siblings))))
+              (car (reverse bounds))
+              (car (reverse all-cols))))
+         (elts-L (ly:grob-array->list (ly:grob-object left-bound 'elements)))
+         (elts-R (ly:grob-array->list (ly:grob-object right-bound 'elements)))
+         (break-alignment-L
+          (filter
+           (lambda (elt) (grob::has-interface elt 'break-alignment-interface))
+           elts-L))
+         (break-alignment-R
+          (filter
+           (lambda (elt) (grob::has-interface elt 'break-alignment-interface))
+           elts-R))
+         (break-alignment-L-ext (ly:grob-extent (car break-alignment-L) refp X))
+         (break-alignment-R-ext (ly:grob-extent (car break-alignment-R) refp X))
+         (num (markup (number->string (ly:grob-property grob 'count-from))))
+         (num
+          (if (or (null? siblings)
+                  (eq? grob (car siblings)))
+              num
+              (make-parenthesize-markup num)))
+         (num (grob-interpret-markup grob num))
+         (num (ly:stencil-aligned-to num X (ly:grob-property grob 'self-alignment-X)))
+         (num
+          (ly:stencil-translate-axis
+           num
+           (+ (interval-length break-alignment-L-ext)
+              (* 0.5
+                 (- (car break-alignment-R-ext)
+                    (cdr break-alignment-L-ext))))
+           X)))
+    num))

 
 

-   (if (>= (length siblings) 2)
-       (helper siblings arg)
-       (car arg))))
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; The following are used by the \offset function
+
+(define (find-value-to-offset prop self alist)
+  "Return the first value of the property @var{prop} in the property
+alist @var{alist} -- after having found @var{self}.  If @var{self} is
+not found, return the first value of @var{prop}."
+  (let ((segment (member (cons prop self) alist)))
+    (if (not segment)
+        (assoc-get prop alist)
+        (assoc-get prop (cdr segment)))))
+
+(define (offset-multiple-types arg offsets)
+  "Displace @var{arg} by @var{offsets} if @var{arg} is a number, a
+number pair, or a list of number pairs.  If @var{offsets} is an empty
+list or if there is a type-mismatch, @var{arg} will be returned."
+  (cond
+    ((and (number? arg) (number? offsets))
+     (+ arg offsets))
+    ((and (number-pair? arg)
+          (or (number? offsets)
+              (number-pair? offsets)))
+     (coord-translate arg offsets))
+    ((and (number-pair-list? arg) (number-pair-list? offsets))
+     (map
+       (lambda (x y) (coord-translate x y))
+       arg offsets))
+    (else arg)))
+
+(define-public (offsetter property offsets)
+  "Apply @var{offsets} to the default values of @var{property} of @var{grob}.
+Offsets are restricted to immutable properties and values of type @code{number},
+@code{number-pair}, or @code{number-pair-list}."
+  (define (self grob)
+    (let* ((immutable (ly:grob-basic-properties grob))
+           ; We need to search the basic-properties alist for our property to
+           ; obtain values to offset.  Our search is complicated by the fact that
+           ; calling the music function `offset' as an override conses a pair to
+           ; the head of the alist.  This pair must be discounted.  The closure it
+           ; contains is named `self' so it can be easily recognized.  If `offset'
+           ; is called as a tweak, the basic-property alist is unaffected.
+           (target (find-value-to-offset property self immutable))
+           ; if target is a procedure, we need to apply it to our grob to calculate
+           ; values to offset.
+           (vals
+             (if (procedure? target)
+                 (target grob)
+                 target))
+           (can-type-be-offset?
+             (or (number? vals)
+                 (number-pair? vals)
+                 (number-pair-list? vals))))
+
+      (if can-type-be-offset?
+          ; '(+inf.0 . -inf.0) would offset to itself.  This will be confusing to a
+          ; user unaware of the default value of the property, so issue a warning.
+          (if (equal? empty-interval vals)
+              (ly:warning "default '~a of ~a is ~a and can't be offset"
+                property grob vals)
+              (let* ((orig (ly:grob-original grob))
+                     (siblings
+                       (if (ly:spanner? grob)
+                           (ly:spanner-broken-into orig)
+                           '()))
+                     (total-found (length siblings))
+                     ; Since there is some flexibility in input syntax,
+                     ; structure of `offsets' is normalized.
+                     (offsets
+                       (if (or (not (pair? offsets))
+                               (number-pair? offsets)
+                               (and (number-pair-list? offsets)
+                                    (number-pair-list? vals)))
+                           (list offsets)
+                           offsets)))
+
+                (define (helper sibs offs)
+                  ; apply offsets to the siblings of broken spanners
+                  (if (pair? offs)
+                      (if (eq? (car sibs) grob)
+                          (offset-multiple-types vals (car offs))
+                          (helper (cdr sibs) (cdr offs)))
+                      vals))
+
+                (if (>= total-found 2)
+                    (helper siblings offsets)
+                    (offset-multiple-types vals (car offsets)))))
+
+              (begin
+                (ly:warning "the property '~a of ~a cannot be offset" property grob)
+                vals))))
+    ; return the closure named `self'
+    self)