Re: Writing multiple-voiced music in chords -- adjusting the syntax or finding a magic trick?

[Aaron Hill]

On 2022-06-28 5:17 pm, Petr Pařízek via Discussions on LilyPond 
development wrote:
> Dan wrote:
> > Are you aware  of \parallelMusic ?
>
> AFAIK, \parallelMusic requires me to write one full measure of each
> voice while interleaving the voices.
> As long as I'm writing it all into one stave, there's little
> difference in doing it this way from enclosing each measure in braces
> and putting "\\" between them.

\parallelMusic defines music variables, which is significantly different 
than the << \\ >> construct which only instantiates voices.


> What's more, even if I did use \parallelMusic, I'm not sure how I
> would be supposed to decipher that the "d3-f3-A3-F4" in my example
> would sound all at the same time.

To use \parallelMusic, you should only need to rotate your thinking.  
Instead of simultaneous notes being in the same row, you are able to 
freely space such notes to align them in columns, similar to that of 
traditional notation.  (I should note that such horizontal alignment is 
purely for the sake of the human, as LilyPond largely ignores 
whitespace.)

%%%%
\version "2.22.0"

%{
    vvv  vvv  vvv  vvv
    ---  ---  ---  ---
    c3o  g3h  C4h. E4h
         g3h       E4h
              C4q
    d3o  f3o  A3h  F4q
                   E4h
              B3h
                   D4q
    c3o  g3o  C4o  E4o

  (swap rows/columns)

  >| E4h  E4h       F4q  E4h       D4q  E4o
  >| C4h.      C4q  A3h       B3h       C4o
  >| g3h  g3h       f3o                 g3o
  >| c3o            d3o                 c3o
%}

\parallelMusic upperA, upperB, lowerA, lowerB {
  e2      e2      f4  e2      d4  e1 |
  c2.         c4  a2      b2      c1 |
  g2      g2      f1              g1 |
  c1              d1              c1 |
}

\new PianoStaff <<
  \new Staff { \clef treble
    << \relative c' \upperA \\ \relative c' \upperB >>
  }
  \new Staff { \clef bass
    << \relative c \lowerA \\ \relative c \lowerB >>
  }
> >
%%%%

----

It might be possible to support input similar to the original row-based 
approach.  Consider a possible function:

%%%%
\seriesMusic lowerB, lowerA, upperB, upperA {
  | c1    g2    c2.   e2
          g2          e2
                c4
  | d1    f1    a2    f4
                      e2
                b2
                      d4
  | c1    g1    c1    e1
}
%%%%

(NOTE: I picked the word "series" as an opposite to "parallel", though I 
concede it is likely a dumb name.)

Implementing \seriesMusic amounts to assigning each note to the 
specified variables in a round-robin fashion, skipping over those that 
have an incomplete duration.  After each row of input, the shortest 
remaining duration is used as the virtual time step.  Bar checks would 
be applied to each music variable, and they might also help catch input 
errors, as this function would not be able to see the actual rows of 
input as delimited by newlines.

Ties, slurs, and articulations should probably work as expected.  
However, tuplets become much harder to input.  The normal syntax of 
\tuplet <fraction> { ... } assumes a left-to-right reading order.  It 
would never work in a column, so the user would have to use scaled 
durations (e.g. d4*2/3).  Such durations would have be manually repeated 
each row.  Similar issues would apply to any construct that surrounds 
notes, such as \transpose.  And while \overrides and \tweaks could be 
assigned to whatever variable is currently awaiting a note, they will 
certainly disturb the alignment of notes.

Ultimately, this is probably only a viable input method for simple 
music.  As things get even slightly more complex, writing parts in the 
more traditional manner likely wins out for readability and 
maintainability.


-- Aaron Hill