## 1.3 Music properties

`absolute-octave` (integer)

  The absolute octave for an octave check note.

`alteration` (number)

  Alteration for figured bass.

`alternative-dir` (direction)

  Indicates if an AlternativeMusic is the First (-1), Middle (0), or Last (1) of group of alternate endings.

`alternative-increment` (integer)

  The number of times an alternative’s lettering should be incremented.

`articulation-type` (string)

  Key for script definitions alist.

  TODO: Consider making type into symbol.

`articulations` (list of music objects)

  Articulation events specifically for this note.

`associated-context` (string)

  Name of the Voice context associated with this `\lyricsto` section.

`augmented` (boolean)

  This figure is for an augmented figured bass (with `+` sign).

`augmented-slash` (boolean)

  This figure is for an augmented figured bass (back-slashed number).

`automatically-numbered` (boolean)

  Should a footnote be automatically numbered?

`autosplit-end` (boolean)

  Duration of event was truncated by automatic splitting in `Completion_heads_engraver`.

`bass` (boolean)

  Set if this note is a bass note in a chord.

`beat-structure` (list)

  A beatStructure to be used in autobeaming.

`bracket-start` (boolean)

  Start a bracket here.

  TODO: Use SpanEvents?

`bracket-stop` (boolean)

  Stop a bracket here.

`break-penalty` (number)

  Penalty for line break hint.

`break-permission` (symbol)

  Whether to allow, forbid or force a line break.

`cautionary` (boolean)

  If set, this alteration needs a cautionary accidental.

`change-to-id` (string)

  Name of the context to change to.

`change-to-type` (symbol)

  Type of the context to change to.

`class` (symbol)

  The class name of an event class.

`compress-procedure` (procedure)

  Compress this music expression. Arg 1: the music, arg 2: factor.

`context` (context)

  The context to which an event is sent.

`context-id` (string)

  Name of context.

`context-type` (symbol)

  Type of context.

`create-new` (boolean)

  Create a fresh context.

`delta-step` (number)

  How much should a fall change pitch?

`denominator` (integer)

  Denominator in a time signature.

`descend-only` (boolean)

  If set, this `\context` only descends in the context tree.

`digit` (integer)

  Digit for fingering.

`diminished` (boolean)

  This bass figure should be slashed.

`direction` (direction)

  Print this up or down?

`drum-type` (symbol)

  Which percussion instrument to play this note on.

`duration` (duration)

  Duration of this note or lyric.

`element` (music)

  The single child of a Music_wrapper music object, or the body of a repeat.

`elements` (list of music objects)

  A list of elements for sequential of simultaneous music, or the alternatives of repeated music.

`elements-callback` (procedure)

  Return a list of children, for use by a sequential iterator. Takes a single music parameter.

`error-found` (boolean)

  If true, a parsing error was found in this expression.

`events` (list)

  A list of events contained in this event.

`figure` (integer)

  A bass figure.

`footnote-text` (markup)

  Text to appear in a footnote.

`force-accidental` (boolean)

  If set, a cautionary accidental should always be printed on this note.

`forced-type` (symbol)

  Override for the part-combiner.

`grob-property` (symbol)

  The symbol of the grob property to set.

`grob-property-path` (list)

  A list of symbols, locating a nested grob property, e.g., `(beamed-lengths details)`.

`grob-value` (any type)

  The value of the grob property to set.

`id` (symbol)

  The ID of an event.

`input-tag` (any type)

  Arbitrary marker to relate input and output.

`inversion` (boolean)

  If set, this chord note is inverted.

`iterator-ctor` (procedure)

  Function to construct a `music-event-iterator` object for this music.

`label` (markup)

  Label of a mark.

`last-pitch` (pitch)

  The last pitch after relativization.

`length` (moment)

  The duration of this music.

`length-callback` (procedure)

  How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

`line-break-permission` (symbol)

  When the music is at top-level, whether to allow, forbid or force a line break.

`metronome-count` (number or pair)

  How many beats in a minute?

`moment` (moment)

  The moment at which an event happens.

`music-cause` (music)

  The music object that is the cause of an event.

`name` (symbol)

  Name of this music object.

`no-continuation` (boolean)

  If set, disallow continuation lines.

`numerator` (integer)

  Numerator of a time signature.

`octavation` (integer)

  This pitch was octavated by how many octaves? For chord inversions, this is negative.

`once` (boolean)

  Apply this operation only during one time step?

`ops` (any type)

  The operations to apply during the creation of a context.

`origin` (input location)

  Where was this piece of music defined?

`ottava-number` (integer)

  The octavation for `\ottava`.

`page-break-permission` (symbol)

  When the music is at top-level, whether to allow, forbid or force a page break.

`page-label` (symbol)

  The label of a page marker.

`page-marker` (boolean)

  If true, and the music expression is found at top-level, a page marker object is instanciated instead of a score.

`page-turn-permission` (symbol)

  When the music is at top-level, whether to allow, forbid or force a page turn.

`parenthesize` (boolean)

  Enclose resulting objects in parentheses?

`part-combine-status` (symbol)

  Change to what kind of state? Options are `solo1`, `solo2` and `unisono`.

`pitch` (pitch)

  The pitch of this note.

`pitch-alist` (list)

  A list of pitches jointly forming the scale of a key signature.

`pop-first` (boolean)

  Do a revert before we try to do an override on some grob property.

`prob-property` (symbol)

  The symbol of the prob property to set.

`procedure` (procedure)

  The function to run with `\applycontext`. It must take a single argument, being the context.

`property-operations` (list)

  Do these operations for instantiating the context.

`property-path` (symbol)

  The path of a property.

`quoted-context-id` (string)

  The ID of the context to direct quotes to, e.g., `cue`.

`quoted-context-type` (symbol)

  The name of the context to direct quotes to, e.g., `Voice`.

`quoted-events` (vector)

  A vector of with `moment` and `event-list` entries.

`quoted-music-clef` (string)

  The clef of the voice to quote.

`quoted-music-name` (string)

  The name of the voice to quote.

`quoted-transposition` (pitch)

  The pitch used for the quote, overriding `\transposition`.

`quoted-voice-direction` (direction)

  Should the quoted voice be up-stem or down-stem?

`repeat-count` (integer)

  Do a `\repeat` how often?

`slash-count` (integer)

  The number of slashes in a single-beat repeat. If zero, signals a beat containing varying durations.

`span-direction` (direction)

  Does this start or stop a spanner?

`span-text` (markup)

  The displayed text for dynamic text spanners (e.g., cresc.)

`span-type` (symbol)

  What kind of dynamic spanner should be created? Options are `'text` and `'hairpin`.

`spanner-id` (string)

  Identifier to distinguish concurrent spanners.

`split-list` (list)

  Splitting moments for part combiner.

`start-callback` (procedure)

  Function to compute the negative length of starting grace notes. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

`string-number` (integer)

  The number of the string in a `StringNumberEvent`.

`symbol` (symbol)

  Grob name to perform an override or revert on.

`tags` (list)

  List of symbols that for denoting extra details, e.g., `\tag #'part …` could tag a piece of music as only being active in a part.

`tempo-unit` (duration)

  The unit for the metronome count.

`text` (markup)

  Markup expression to be printed.

`to-relative-callback` (procedure)

  How to transform a piece of music to relative pitches.

`tonic` (pitch)

  Base of the scale.

`tremolo-type` (integer)

  Speed of tremolo, e.g., 16 for `c4:16`.

`trill-pitch` (pitch)

  Pitch of other note of the trill.

`tweaks` (list)

  An alist of properties to override in the backend for the grob made of this event.

`type` (symbol)

  The type of this music object. Determines iteration in some cases.

`types` (list)

  The types of this music object; determines by what engraver this music expression is processed.

`untransposable` (boolean)

  If set, this music is not transposed.

`value` (any type)

  Assignment value for a translation property.

`void` (boolean)

  If this property is `#t`, then the music expression is to be discarded by the toplevel music handler.

`volta-repeats` (list)

  A list that is transformed into a volta repeat element list.

`what` (symbol)

  What to change for auto-change.

  FIXME: Naming.

`X-offset` (number)

  Offset of resulting grob; only used for balloon texts.

`Y-offset` (number)

  Offset of resulting grob; only used for balloon texts.

#### Internals Reference v2.18.2 (稳定分支).