X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=ly%2Fmusic-functions-init.ly;h=7d9f5b7034b2fcf8011e02b8d997d0a9746cf5e1;hb=47db9a3883d726ca53e2133a3b2298f78dd6a32e;hp=8af797115f6a730b08e4ee153c71ac939f031591;hpb=32689b75bec62313992c1b452f624d65f45e8789;p=lilypond.git diff --git a/ly/music-functions-init.ly b/ly/music-functions-init.ly index 8af797115f..7d9f5b7034 100644 --- a/ly/music-functions-init.ly +++ b/ly/music-functions-init.ly @@ -2,7 +2,7 @@ %%%% This file is part of LilyPond, the GNU music typesetter. %%%% -%%%% Copyright (C) 2003--2012 Han-Wen Nienhuys +%%%% Copyright (C) 2003--2015 Han-Wen Nienhuys %%%% Jan Nieuwenhuizen %%%% %%%% LilyPond is free software: you can redistribute it and/or modify @@ -221,6 +221,14 @@ barNumberCheck = "Barcheck failed got ~a expect ~a" cbn n)))))) +beamExceptions = +#(define-scheme-function (parser location music) (ly:music?) + (_i "Extract a value suitable for setting +@code{Timing.beamExceptions} from the given pattern with explicit +beams in @var{music}. A bar check @code{|} has to be used between +bars of patterns in order to reset the timing.") + (extract-beam-exceptions music)) + bendAfter = #(define-event-function (parser location delta) (real?) (_i "Create a fall or doit of pitch interval @var{delta}.") @@ -270,8 +278,8 @@ as @code{\\compoundMeter #'((3 2 8))} or shorter (timesig (cons (ly:moment-main-numerator mlen) (ly:moment-main-denominator mlen)))) #{ - \once \override Staff.TimeSignature.stencil = #(lambda (grob) - (grob-interpret-markup grob (format-compound-time args))) + \once \override Timing.TimeSignature.stencil = #(lambda (grob) + (grob-interpret-markup grob (make-compound-meter-markup args))) \set Timing.timeSignatureFraction = #timesig \set Timing.baseMoment = #beat \set Timing.beatStructure = #beatGrouping @@ -307,7 +315,7 @@ cueDuring = in a CueVoice oriented by @var{dir}.") (make-music 'QuoteMusic 'element main-music - 'quoted-context-type 'Voice + 'quoted-context-type 'CueVoice 'quoted-context-id "cue" 'quoted-music-name what 'quoted-voice-direction dir)) @@ -319,7 +327,7 @@ cueDuringWithClef = in a CueVoice oriented by @var{dir}.") (make-music 'QuoteMusic 'element main-music - 'quoted-context-type 'Voice + 'quoted-context-type 'CueVoice 'quoted-context-id "cue" 'quoted-music-name what 'quoted-music-clef clef @@ -328,20 +336,32 @@ in a CueVoice oriented by @var{dir}.") displayLilyMusic = -#(define-music-function (parser location music) (ly:music?) +#(define-music-function (parser location port music) ((output-port?) ly:music?) (_i "Display the LilyPond input representation of @var{music} -to the console.") - (newline) - (display-lily-music music parser) +to @var{port}, defaulting to the console.") + (let ((port (or port (current-output-port)))) + (newline port) + (display-lily-music music parser port)) music) displayMusic = -#(define-music-function (parser location music) (ly:music?) - (_i "Display the internal representation of @var{music} to the console.") - (newline) - (display-scheme-music music) +#(define-music-function (parser location port music) ((output-port?) ly:music?) + (_i "Display the internal representation of @var{music} to +@var{port}, default to the console.") + (let ((port (or port (current-output-port)))) + (newline port) + (display-scheme-music music port)) music) +displayScheme = +#(define-scheme-function (parser location port expr) ((output-port?) scheme?) + (_i "Display the internal representation of @var{expr} to +@var{port}, default to the console.") + (let ((port (or port (current-output-port)))) + (newline port) + (display-scheme-music expr port)) + expr) + endSpanners = @@ -427,7 +447,7 @@ to the preceding note or rest as a post-event with @code{-}.") 'automatically-numbered (not mark) 'text (or mark (make-null-markup)) 'footnote-text footnote))) - #{ \tweak footnote-music #mus #item #})) + #{ \once \tweak footnote-music #mus #item #})) grace = #(def-grace-function startGraceMusic stopGraceMusic @@ -439,8 +459,8 @@ grobdescriptions = in the format of @code{all-grob-descriptions}.") (ly:make-context-mod (map (lambda (p) - (list 'assign (car p) (list (cdr p)))) - descriptions))) + (list 'assign (car p) (ly:make-grob-properties (cdr p)))) + descriptions))) harmonicByFret = #(define-music-function (parser location fret music) (number? ly:music?) (_i "Convert @var{music} into mixed harmonics; the resulting notes resemble @@ -488,9 +508,7 @@ If @var{item} is a symbol list of form @code{GrobName} or @code{Context.GrobName}, the result is an override for the grob name specified by it. If @var{item} is a music expression, the result is the same music expression with an appropriate tweak applied to it.") - (if (ly:music? item) - #{ \tweak transparent ##t #item #} - #{ \override #item . transparent = ##t #})) + #{ \tweak transparent ##t #item #}) inStaffSegno = #(define-music-function (parser location) () @@ -528,21 +546,18 @@ instrumentSwitch = keepWithTag = -#(define-music-function (parser location tag music) +#(define-music-function (parser location tags music) (symbol-list-or-symbol? ly:music?) - (_i "Include only elements of @var{music} that are either untagged -or tagged with one of the tags in @var{tag}. @var{tag} may be either -a single symbol or a list of symbols.") + (_i "Include only elements of @var{music} that are tagged with one +of the tags in @var{tags}. @var{tags} may be either a single symbol +or a list of symbols. + +Each tag may be declared as a member of at most one tag group (defined +with @code{\\tagGroup}). If none of a @var{music} element's tags +share a tag group with one of the specified @var{tags}, the element is +retained.") (music-filter - (if (symbol? tag) - (lambda (m) - (let ((music-tags (ly:music-property m 'tags))) - (or (null? music-tags) - (memq tag music-tags)))) - (lambda (m) - (let ((music-tags (ly:music-property m 'tags))) - (or (null? music-tags) - (any (lambda (t) (memq t music-tags)) tag))))) + (tags-keep-predicate tags) music)) key = @@ -606,6 +621,138 @@ languageRestore = (ly:input-warning location (_ "No other language was defined previously. Ignoring.")))) +magnifyMusic = +#(define-music-function (parser location mag music) (positive? ly:music?) + (_i "Magnify the notation of @var{music} without changing the +staff-size, using @var{mag} as a size factor. Stems, beams, +slurs, ties, and horizontal spacing are adjusted automatically.") + + ;; these props are NOT allowed to shrink below default size + (define unshrinkable-props + '( + ;; stems + (Stem thickness) + + ;; slurs + (Slur line-thickness) + (Slur thickness) + (PhrasingSlur line-thickness) + (PhrasingSlur thickness) + + ;; ties + (Tie line-thickness) + (Tie thickness) + (LaissezVibrerTie line-thickness) + (LaissezVibrerTie thickness) + (RepeatTie line-thickness) + (RepeatTie thickness) + )) + + ;; these props ARE allowed to shrink below default size + (define shrinkable-props + (let ((baseline-skip-props + (find-named-props 'baseline-skip all-grob-descriptions)) + (word-space-props + (find-named-props 'word-space all-grob-descriptions))) + (append + baseline-skip-props + word-space-props + '( + ;; TODO: uncomment spacing-increment here once Issue 3987 is fixed + ;; override at the 'Score level + ;(SpacingSpanner spacing-increment) + + ;; lengths and heights + (Beam length-fraction) + (Stem length-fraction) + (Stem beamlet-default-length) + (Stem double-stem-separation) + (Slur height-limit) + (Slur minimum-length) + (PhrasingSlur height-limit) + (PhrasingSlur minimum-length) + + ;; Beam.beam-thickness is dealt with separately below + )))) + #{ + \context Bottom { + %% TODO: uncomment \newSpacingSection once Issue 3990 is fixed + %\newSpacingSection + #(scale-fontSize 'magnifyMusic mag) + #(scale-props 'magnifyMusic mag #f unshrinkable-props) + #(scale-props 'magnifyMusic mag #t shrinkable-props) + #(scale-beam-thickness mag) + + #music + + %% TODO: uncomment \newSpacingSection once Issue 3990 is fixed + %\newSpacingSection + %% reverse engineer the former fontSize value instead of using \unset + #(revert-fontSize 'magnifyMusic mag) + #(revert-props 'magnifyMusic mag (append unshrinkable-props + shrinkable-props + '((Beam beam-thickness)))) + } + #}) + +magnifyStaff = +#(define-music-function (parser location mag) (positive?) + (_i "Change the size of the staff, adjusting notation size and +horizontal spacing automatically, using @var{mag} as a size factor.") + + ;; these props are NOT allowed to shrink below default size + (define unshrinkable-props + '((StaffSymbol thickness))) + + ;; these props ARE allowed to shrink below default size + (define shrinkable-props + (let* ((baseline-skip-props + (find-named-props 'baseline-skip all-grob-descriptions)) + (word-space-props + (find-named-props 'word-space all-grob-descriptions)) + (space-alist-props + (find-named-props 'space-alist all-grob-descriptions))) + (append + baseline-skip-props + word-space-props + space-alist-props + '( + ;; override at the 'Score level + (SpacingSpanner spacing-increment) + + (StaffSymbol staff-space) + (BarLine kern) + (BarLine segno-kern) + (BarLine hair-thickness) + (BarLine thick-thickness) + (Stem beamlet-default-length) + (Stem double-stem-separation) + )))) + + #{ + \stopStaff + + %% revert settings from last time + %% (but only if \magnifyStaff has already been used + %% and the staff magnification is changing) + #(revert-fontSize 'magnifyStaff mag) + #(revert-props 'magnifyStaff mag (append unshrinkable-props + shrinkable-props)) + + %% scale settings + %% (but only if staff magnification is changing + %% and does not equal 1) + #(scale-fontSize 'magnifyStaff mag) + #(scale-props 'magnifyStaff mag #f unshrinkable-props) + #(scale-props 'magnifyStaff mag #t shrinkable-props) + + %% this might cause problems until Issue 3990 is fixed + \newSpacingSection + + \startStaff + \set Staff.magnifyStaffValue = #mag + #}) + makeClusters = #(define-music-function (parser location arg) (ly:music?) (_i "Display chords in @var{arg} as clusters.") @@ -687,6 +834,48 @@ octaveCheck = (make-music 'RelativeOctaveCheck 'pitch pitch)) +offset = +#(define-music-function (parser location property offsets item) + (symbol-list-or-symbol? scheme? symbol-list-or-music?) + (_i "Offset the default value of @var{property} of @var{item} by +@var{offsets}. If @var{item} is a string, the result is +@code{\\override} for the specified grob type. If @var{item} is +a music expression, the result is the same music expression with an +appropriate tweak applied.") + (if (ly:music? item) + ; In case of a tweak, grob property path is Grob.property + (let ((prop-path (check-grob-path + (if (symbol? property) + (list property) + property) + parser location + #:start 1 #:default #t #:min 2 #:max 2))) + (if prop-path + ; If the head of the grob property path is a symbol--i.e., + ; a grob name, produce a directed tweak. Otherwise, create + ; an ordinary tweak. + (if (symbol? (car prop-path)) + #{ + \tweak #prop-path #(offsetter (second prop-path) offsets) #item + #} + #{ + \tweak #(second prop-path) #(offsetter (second prop-path) offsets) #item + #}) + item)) + ; In case of an override, grob property path is Context.Grob.property. + (let ((prop-path (check-grob-path + (append item + (if (symbol? property) + (list property) + property)) + parser location + #:default 'Bottom #:min 3 #:max 3))) + (if prop-path + #{ + \override #prop-path = #(offsetter (third prop-path) offsets) + #} + (make-music 'Music))))) + omit = #(define-music-function (parser location item) (symbol-list-or-music?) (_i "Set @var{item}'s @samp{stencil} property to @code{#f}, @@ -696,21 +885,28 @@ If @var{item} is a symbol list of form @code{GrobName} or @code{Context.GrobName}, the result is an override for the grob name specified by it. If @var{item} is a music expression, the result is the same music expression with an appropriate tweak applied to it.") - (if (ly:music? item) - #{ \tweak stencil ##f #item #} - #{ \override #item . stencil = ##f #})) + #{ \tweak stencil ##f #item #}) once = #(define-music-function (parser location music) (ly:music?) - (_i "Set @code{once} to @code{#t} on all layout instruction events in @var{music}.") - (music-map - (lambda (m) - (cond ((music-is-of-type? m 'layout-instruction-event) - (set! (ly:music-property m 'once) #t)) - ((ly:duration? (ly:music-property m 'duration)) - (ly:music-warning m (_ "Cannot apply \\once to timed music")))) - m) - music)) + (_i "Set @code{once} to @code{#t} on all layout instruction events +in @var{music}. This will complain about music with an actual +duration. As a special exception, if @var{music} contains +@samp{tweaks} it will be silently ignored in order to allow for +@code{\\once \\tweak} to work as both one-time override and proper +tweak.") + (if (not (pair? (ly:music-property music 'tweaks))) + (for-some-music + (lambda (m) + (cond ((music-is-of-type? m 'layout-instruction-event) + (set! (ly:music-property m 'once) #t) + #t) + ((ly:duration? (ly:music-property m 'duration)) + (ly:music-warning m (_ "Cannot apply \\once to timed music")) + #t) + (else #f))) + music)) + music) ottava = #(define-music-function (parser location octave) (integer?) @@ -721,7 +917,7 @@ ottava = overrideTimeSignatureSettings = #(define-music-function (parser location time-signature base-moment beat-structure beam-exceptions) - (pair? pair? cheap-list? cheap-list?) + (fraction? fraction? list? list?) (_i "Override @code{timeSignatureSettings} for time signatures of @var{time-signature} to have settings @@ -812,100 +1008,101 @@ Example: C = { e e | f f | } @end verbatim ") + (define voice-count (length voice-ids)) (define (bar-check? m) "Checks whether m is a bar check." (eq? (ly:music-property m 'name) 'BarCheck)) + (define (recurse-and-split-list lst) + "Return either a list of music lists split along barchecks, or @code{#f}." + (if (any bar-check? lst) + (let* ((voices (apply circular-list (make-list voice-count '()))) + (current-voices voices) + (current-sequence '())) + ;; + ;; utilities + (define (push-music m) + "Push the music expression into the current sequence" + (set! current-sequence (cons m current-sequence))) + (define (change-voice) + "Store the previously built sequence into the current voice and +change to the following voice." + (set-car! current-voices + (cons (reverse! current-sequence) + (car current-voices))) + (set! current-sequence '()) + (set! current-voices (cdr current-voices))) + (for-each (lambda (m) + (let ((split? (recurse-and-split m))) + (if split? + (for-each + (lambda (m) + (push-music m) + (change-voice)) + split?) + (begin + (push-music m) + (if (bar-check? m) (change-voice)))))) + lst) + (if (pair? current-sequence) (change-voice)) + ;; un-circularize `voices' and reorder the voices + (set! voices (map reverse! + (list-head voices voice-count))) + ;; check sequence length + (apply for-each (lambda seqs + (define (seq-len seq) + (reduce ly:moment-add + (ly:make-moment 0) + (map ly:music-length seq))) + (let ((moment-reference (seq-len (car seqs)))) + (for-each (lambda (seq) + (if (not (equal? (seq-len seq) + moment-reference)) + (ly:music-warning + (if (pair? seq) + (last seq) + (caar seqs)) + (_ "Bars in parallel music don't have the same length")))) + seqs))) + voices) + (map concatenate! voices)) + (let ((deeper (map recurse-and-split lst))) + (and (any pair? deeper) + (apply zip (map + (lambda (m split) + (or split + (ly:music-deep-copy (make-list voice-count m)))) + lst deeper)))))) (define (recurse-and-split music) "This returns either a list of music split along barchecks, or @code{#f}." - (let ((elt (ly:music-property music 'element)) - (elts (ly:music-property music 'elements))) - (cond ((ly:music? elt) - (let ((lst (recurse-and-split elt))) - (and lst - (map - (lambda (x) - (let ((res (music-clone music 'element x))) - (if (ly:input-location? - (ly:music-property x 'origin)) - (set! (ly:music-property res 'origin) - (ly:music-property x 'origin))) - res)) - lst)))) - ((any bar-check? elts) - (let* ((voices (apply circular-list - (make-list (length voice-ids) - '()))) - (current-voices voices) - (current-sequence '())) - ;; - ;; utilities - (define (push-music m) - "Push the music expression into the current sequence" - (set! current-sequence (cons m current-sequence))) - (define (change-voice) - "Stores the previously built sequence into the current voice and - change to the following voice." - (set-car! current-voices - (cons (reverse! current-sequence) - (car current-voices))) - (set! current-sequence '()) - (set! current-voices (cdr current-voices))) - (for-each (lambda (m) - (let ((split? (recurse-and-split m))) - (if split? - (for-each - (lambda (m) - (push-music m) - (change-voice)) - split?) - (begin - (push-music m) - (if (bar-check? m) (change-voice)))))) - elts) - (if (pair? current-sequence) (change-voice)) - ;; un-circularize `voices' and reorder the voices - - (set! voices (map reverse! - (list-head voices (length voice-ids)))) - - ;; check sequence length - (apply for-each (lambda seqs - (define (seq-len seq) - (reduce ly:moment-add - (ly:make-moment 0) - (map ly:music-length seq))) - (let ((moment-reference (seq-len (car seqs)))) - (for-each (lambda (seq) - (if (not (equal? (seq-len seq) - moment-reference)) - (ly:music-warning - (if (pair? seq) - (last seq) - (caar seqs)) - (_ "Bars in parallel music don't have the same length")))) - seqs))) - voices) - (map - (lambda (lst) - (set! lst (concatenate! lst)) - (let ((res (music-clone music 'elements lst))) - (if (and (pair? lst) - (ly:input-location? (ly:music-property - (car lst) - 'origin))) - (set! (ly:music-property res 'origin) - (ly:music-property (car lst) 'origin))) - res)) - voices))) - (else #f)))) + (let* ((elt (ly:music-property music 'element)) + (elts (ly:music-property music 'elements)) + (split-elt (and (ly:music? elt) (recurse-and-split elt))) + (split-elts (and (pair? elts) (recurse-and-split-list elts)))) + (and (or split-elt split-elts) + (map + (lambda (e es) + (apply music-clone music + (append + ;; reassigning the origin of the parent only + ;; makes sense if the first expression in the + ;; result is from a distributed origin + (let ((origin + (if (ly:music? elt) + (and (ly:music? e) (ly:music-property e 'origin #f)) + (and (pair? es) (ly:music-property (car es) 'origin #f))))) + (if origin (list 'origin origin) '())) + (if (ly:music? e) (list 'element e) '()) + (if (pair? es) (list 'elements es) '())))) + (or split-elt (circular-list #f)) + (or split-elts (circular-list #f)))))) (let ((voices (recurse-and-split music))) (if voices ;; ;; bind voice identifiers to the voices (for-each (lambda (voice-id voice) (ly:parser-define! parser voice-id voice)) - voice-ids voices) + voice-ids voices) (ly:music-warning music (_ "ignoring parallel music without barchecks"))))) @@ -927,25 +1124,31 @@ parenthesize = arg) partcombine = -#(define-music-function (parser location part1 part2) (ly:music? ly:music?) - (_i "Take the music in @var{part1} and @var{part2} and typeset so -that they share a staff.") +#(define-music-function (parser location chord-range part1 part2) + ((number-pair? '(0 . 8)) ly:music? ly:music?) + (_i "Take the music in @var{part1} and @var{part2} and return +a music expression containing simultaneous voices, where @var{part1} +and @var{part2} are combined into one voice where appropriate. +Optional @var{chord-range} sets the distance in steps between notes +that may be combined into a chord or unison.") (make-part-combine-music parser - (list part1 part2) #f)) + (list part1 part2) #f chord-range)) partcombineUp = -#(define-music-function (parser location part1 part2) (ly:music? ly:music?) +#(define-music-function (parser location chord-range part1 part2) + ((number-pair? '(0 . 8)) ly:music? ly:music?) (_i "Take the music in @var{part1} and @var{part2} and typeset so that they share a staff with stems directed upward.") (make-part-combine-music parser - (list part1 part2) UP)) + (list part1 part2) UP chord-range)) partcombineDown = -#(define-music-function (parser location part1 part2) (ly:music? ly:music?) +#(define-music-function (parser location chord-range part1 part2) + ((number-pair? '(0 . 8)) ly:music? ly:music?) (_i "Take the music in @var{part1} and @var{part2} and typeset so that they share a staff with stems directed downward.") (make-part-combine-music parser - (list part1 part2) DOWN)) + (list part1 part2) DOWN chord-range)) partcombineForce = #(define-music-function (location parser type once) (symbol-or-boolean? boolean?) @@ -1053,19 +1256,13 @@ omitted, the first note in @var{music} is given in absolute pitch.") 'element music)) removeWithTag = -#(define-music-function (parser location tag music) +#(define-music-function (parser location tags music) (symbol-list-or-symbol? ly:music?) (_i "Remove elements of @var{music} that are tagged with one of the -tags in @var{tag}. @var{tag} may be either a single symbol or a list +tags in @var{tags}. @var{tags} may be either a single symbol or a list of symbols.") (music-filter - (if (symbol? tag) - (lambda (m) - (not (memq tag (ly:music-property m 'tags)))) - (lambda (m) - (let ((music-tags (ly:music-property m 'tags))) - (or (null? music-tags) - (not (any (lambda (t) (memq t music-tags)) tag)))))) + (tags-remove-predicate tags) music)) resetRelativeOctave = @@ -1198,7 +1395,7 @@ appropriate tweak applied.") (if (>= total-found 2) (helper siblings offsets) (offset-control-points (car offsets))))) - #{ \tweak control-points #shape-curve #item #}) + #{ \once \tweak control-points #shape-curve #item #}) shiftDurations = #(define-music-function (parser location dur dots arg) @@ -1206,9 +1403,7 @@ shiftDurations = (_i "Change the duration of @var{arg} by adding @var{dur} to the @code{durlog} of @var{arg} and @var{dots} to the @code{dots} of @var{arg}.") - (music-map - (lambda (x) - (shift-one-duration-log x dur dots)) arg)) + (shift-duration-log arg dur dots)) single = #(define-music-function (parser location overrides music) @@ -1263,18 +1458,25 @@ styledNoteHeads = (style-note-heads heads style music)) tag = -#(define-music-function (parser location tag music) (symbol-list-or-symbol? ly:music?) - (_i "Tag the following @var{music} with @var{tag} and return the -result, by adding the single symbol or symbol list @var{tag} to the +#(define-music-function (parser location tags music) (symbol-list-or-symbol? ly:music?) + (_i "Tag the following @var{music} with @var{tags} and return the +result, by adding the single symbol or symbol list @var{tags} to the @code{tags} property of @var{music}.") (set! (ly:music-property music 'tags) - ((if (symbol? tag) cons append) - tag + ((if (symbol? tags) cons append) + tags (ly:music-property music 'tags))) music) +tagGroup = +#(define-void-function (parser location tags) (symbol-list?) + (_i "Define a tag group comprising the symbols in the symbol list +@var{tags}. Tag groups must not overlap.") + (let ((err (define-tag-group tags))) + (if err (ly:parser-error parser err location)))) + temporary = #(define-music-function (parser location music) (ly:music?) @@ -1357,7 +1559,7 @@ as a first or second voice.") (make-music 'QuoteMusic 'element main-music - 'quoted-context-type 'Voice + 'quoted-context-type 'CueVoice 'quoted-context-id "cue" 'quoted-music-name what 'quoted-voice-direction dir @@ -1426,10 +1628,14 @@ an indirectly created grob (@samp{Accidental} is caused by are affected. As a special case, @var{item} may be a symbol list specifying a grob -path, in which case @code{\\once\\override} is called on it instead of +path, in which case @code{\\override} is called on it instead of creating tweaked music. This is mainly useful when using @code{\\tweak} as as a component for building other functions. +If this use case would call for @code{\\once \\override} rather than a +plain @code{\\override}, writing @code{\\once \\tweak @dots{}} can be +convenient. + @var{prop} can contain additional elements in which case a nested property (inside of an alist) is tweaked.") (if (ly:music? item) @@ -1449,12 +1655,12 @@ property (inside of an alist) is tweaked.") ;; We could just throw this at \override and let it sort this ;; out on its own, but this way we should get better error ;; diagnostics. - (let ((a (check-grob-path item parser location - #:default 'Bottom #:min 2 #:max 2)) - (b (check-grob-path prop parser location - #:start 2))) - (if (and a b) - #{ \once\override #(append a b) = #value #} + (let ((p (check-grob-path + (append item (if (symbol? prop) (list prop) prop)) + parser location + #:default 'Bottom #:min 3))) + (if p + #{ \override #p = #value #} (make-music 'Music))))) undo =