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 { }
}