Re:completion_heads_engraver within a bar

[Jim Tisdall]

Many thanks for the help with completion_heads_engraver.

I've got a related question about completion_rest_engraver

In this example, I'm trying to "split" the rhythms in bars of 4/4
time, so that note values that span the beginning of the third
beat, are rewritten with ties.  (The idea is that it's easier to
read rhythms in 2-beat chunks with ties between them.)

But I'm trying to do a similar thing with rests.
I'd like to have the rests that span the 3rd downbeat, to be split
into two rests, the second one starting at the 3rd downbeat.

Either I'm using the wrong syntax for "\with", or the
Completion_rest_engraver just doesn't do what I would desire, or ??

This example score is 4/4 time and I'm asking for adjustments
every 2 beats (with "1/2").  The rests in the 2nd and 3rd bars
span the 3rd downbeat: I'd like to get a quarter rest followed
by an eighth rest, and an eighth rest followed by a quarter rest,
respectively, in those bars.

Peace,
Jim

\version "2.16.0"
\score {
  \new Staff {
    \clef "treble_8"
    \key c \major
    \time 4/4

    \new Voice \with {
      \remove "Note_heads_engraver"
      \consists "Completion_heads_engraver"
      completionUnit = #(ly:make-moment 1/2)
      \remove "Rest_engraver"
      \consists "Completion_rest_engraver"
      completionUnit = #(ly:make-moment 1/2)
    }
    {  r4 c'4. r8 c'4 c'4 r4. c'4. c'4. r4. c'4 r8 c'4. c'4. r8 }
  }
}