Rhythm improvements

• The \time command now supports complex meters which previously required \compoundMeter, though it requires a slightly different syntax. The \compoundMeter command has been renamed to \timeAbbrev.

  {
    \time #'((2 2 2 3) . 8)
    \repeat unfold 9 c'8
  }
  

  

• The new \submeasureBarsOn command enables automatic bar lines between the components of strictly alternating time signatures (not shown), or where specified by setting the new submeasureStructure context property or grouping the beats in the optional argument to the \time command.

  {
    \submeasureBarsOn
    \time #'((3 4) (3 4) (4 3 4)) 25/16
    \repeat unfold 25 c'16
  }
  

  

• The new \polymetric command simplifies notating polymeter with aligned measures by setting scaled metric properties in contexts other than Timing.

  <<
    \new Staff {
      \scaleDurations 4/6 {
        \context Staff \polymetric \time 6,6,6 18/16
        \repeat unfold 18 c'16
      }
    }
    \new Staff {
      \time 3/4
      c'4 4 4
    }
  >>
  

  

• The default auto-beaming settings for 2/8 time have been changed to allow beaming the full measure.
• \enablePolymeter has been renamed to \enablePerStaffTiming to avoid confusion because it is recommended in only a subset of polymetric use cases.
• The TimeSignature.time-signature property replaces the old fraction property. The new property is more general and can be overridden, which allows certain tricks without overriding the stencil property.

  {
    \once \override Timing.TimeSignature.time-signature = #'(-1 . 12)
    R1
  }
  

  

• The \time command now accepts a rational number in the numerator. The TimeSignature grob and \compound-meter markup function have new properties that control the style of fractional parts.

  

• The \time command now accepts a rational number in the denominator to support time signatures with a beat longer than a whole note.

  {
    \override Timing.TimeSignature.denominator-style = #'note
    \time #'(4 . 1/2)
    e'\breve f' g' a'
  }
  

  

• The TimeSignature grob and \compound-meter markup function now support number-over-note time signatures via denominator-style and related properties.

  {
    \override Timing.TimeSignature.style = #'numbered
    \override Timing.TimeSignature.denominator-style = #'note
    \once \override Timing.TimeSignature.time-signature = #'(2 . 8/3)
    \time 6/8
    r4. g'8 8 8
  }
  

  

• \slashedGrace now prints slashed beams.

  {
    \slashedGrace { d'16 e' d' } c'1
    \slashedGrace { d16 e'' d' } c'1
  }
  

  

  Use beam::slashed-stencil to slash arbitrary beams. Set details.slash-side to RIGHT to print the slash at the right side of the beam.

  {
    \override Beam.stencil = #beam::slashed-stencil
    \cadenzaOn
    c'16^[ a' c'']
    c''^[ a' c']
    c'_[ a' c'']
    c''_[ a' c']
    \override Beam.details.slash-side = #RIGHT
    c'16^[ a' c'']
    c''^[ a' c']
    c'_[ a' c'']
    c''_[ a' c']
  }
  

  

  Use the over-beam-height, slash-slope, slash-side, slash-stem-fraction, slash-thickness, and slash-X-positions subproperties of the details property to customize the appearance of the slash.

• It is now possible to right-align different types of bar lines.

  \new StaffGroup
    <<
      \new Staff { \textMark "default" b1 }
      \new Staff { b1 \section }
    >>
  
  \new StaffGroup
    <<
      \new Staff
        { \textMark "right-aligned" b1 }
      \new Staff
        { b1
          \override StaffGroup.BarLine.right-justified = ##t
          \section }
    >>
  

  

• Bar checks (|) now implicitly create contexts. The developers deem this unlikely to impact real-world scores. Please report a bug if you find a problem without an obvious workaround.
• The new span-all-note-heads option may be used to make tuplet brackets span all note heads (not just the stems) as recommended by Gould and Ross.

  

• Automatic beam subdivision has been reworked. Previously, many imperfections could be found in the results of automatic subdivision of many complex beaming patterns due to overreliance of the value of beatBase. Now, LilyPond can correctly subdivide most beaming patterns and no longer uses the value of beatBase to limit beam subdivision. Simply setting subdivideBeams to #t now automatically subdivides all intervals by default. Three new properties have been introduced to tune automatic beam subdivision: beamMinimumSubdivision, beamMaximumSubdivision and respectIncompleteBeams. beamMinimumSubdivision limits subdivision intervals the same way as how beatBase previously did (reducing frequency of subdivided beams). beamMaximumSubdivision limits the number of beamlets removed at subdivisions in general. respectIncompleteBeams limits the number of beamlets at subdivisions where the remaining length would not complete the metric value of the subdivision. Setting beamMinimumSubdivision to the value of beatBase at all times, even when beatBase implicitly changes, preserves old behavior.
• New ‘stacked’ flag glyphs are available. All flag elements of a flag glyph have the same width but are vertically more compact.

  Use \flagStyleStacked to access them; with \flagStyleDefault you can switch back to the standard flag style.

  

• The TimeSignature style 'single-digit has been renamed to 'single-number.