Switching between one staff and two

[Evan Driscoll]

Something that I always have trouble with (I'm only an occasional Lilypond
user) is writing parts that switch from one staff to two and back, and
getting that so it's correct. If there's a relevant section of the manual I
have a hard time finding it, and I often find problems when adapting
previous times I've dealt with this.

I've pasted some example code after my signature I'm having trouble with.
Can anyone help me solve these problems:

   - The way I'm introducing a second staff, I need to use "\with { \omit
   TimeSignature}" or it will display the time signature on one of the staffs
   when it splits. However, there's a time signature change when switching
   back to a single staff, and this prevents it from showing the time
   signature for that staff when it switches back.
   - As can be seen, neither "\with { \once \omit ...}" instead nor "\undo
   \omit TimeSignature" before the end helps. Even if I remove the "\with",
   while it places the time signature it does not show the staff lines under
   it.
   - There's also an empty space to the right of the final bar line before
   it splits. I honestly have no clue why this is here. If I leave out the
   "\with" then it writes the time signature into it -- for *some* reason I
   don't understand -- but not properly set for it to just be invisible here.

More generally, this is an area where I feel I never know what I'm doing
and just throw stuff at the compiler until it works *well enough*, and then
I give up. Is there some fundamental knowledge that I seem to be missing
here? Something I've not been able to find in the manual?

(Also, LilyBin doesn't seem to be a thing any more. Is there any
replacement? I'm not turning something up.)

Thanks,
Evan


\version "2.20.0"
\language "english"

global = {
  \key d \major
  \time 4/4
  \tempo 4=100
}

measures = \relative c' {
  \repeat unfold 5
    \repeat unfold 6 c4
}

cello = \relative c' {
  \global
  c4 c c c |
  \time 3/2
  \measures
  \break

  <<
    {
      \measures
      \break
      \measures
      \break
    }
    \new Staff
    \with { \once \omit TimeSignature }
    {
      \clef bass
      \key d \major

      \measures
      \break
      \measures

      \undo \omit TimeSignature
      \break
    }
  >>

  \break
  \time 2/2
  c4 c c c

}

\score {
  \new GrandStaff
  \new Staff \with {
    instrumentName = "Cello"
    midiInstrument = "cello"
  } { \clef bass \cello }
  \layout { }
  \midi { }
}