lilypond: merging rests in polyphonic staff

[Martin Lejeune]

Hi Everybody,

here's a newbie question.

I tried to configure "merging automatically" of rests in polyphonic staffs (piano) with a snipped, which I found in the manual.

It doesn't work. 

What's the mistake, any idea?

Thanks very much!

Cheers 

Martin

PS:

My example:

Merging rests.ly
Description: Binary data

\version "2.18.2"

\header {

  title = "merging rests"

}

global = { \time 4/4 }

Key = { \key g\major }

%% ------ Piano ------

rhUpper = \relative c''

{

  \voiceOne 

  \Key

  R1*4

g4 r8 g r2 |

}

rhLower = \relative c' {

  \voiceTwo

  \Key

R1*4

b4 r8 b r2 |

}

lhUpper = \relative c' {

  \voiceOne 

  \Key

  R1*4 |

  g4 r8 g r2 | 

}

lhLower = \relative c {

  \voiceTwo

  \Key

  R1*4|

  d4 r8 d r2 | 

}

PianoRH = {

  \clef treble

  \global

  \set Staff.midiInstrument = #"acoustic grand"

  <<

    \new Voice = "one" \rhUpper

    \new Voice = "two" \rhLower

  >>

}

PianoLH = {

  \clef bass

  \global

  \set Staff.midiInstrument = #"acoustic grand"

  <<

    \new Voice = "one" \lhUpper

    \new Voice = "two" \lhLower

  >>

}

piano = {

  <<

    \set PianoStaff.instrumentName = #"Piano"

    \new Staff = "upper" \PianoRH 

    \new Staff = "lower" \PianoLH

     \set Staff.shortInstrumentName = #"p"

  >>

}

\score {

  

  <<

   \new PianoStaff = "piano" \piano

    >>

 

  \layout {

    \context { \Staff \RemoveEmptyStaves }

    \context {

      \Score

      \override BarNumber.padding = #3

      skipBars = ##t

    }

  }

}

the snippet doesn't work:

Merging rest Snippet.ly
Description: Binary data

\version "2.18.2"

 \new Score {

   <<

    \new Staff  <<

      s4-\markup{ LilyPond default, rests in both voices. }

      \relative c'' { c4 d e r | r2  e4 g | R1 } 

      \\

      \relative c'' { c4 b a r | r a g2   | R1 }

    >>       

    \new Staff \with {

      \override RestCollision.positioning-done = #merge-rests-on-positioning

    } 

    <<

      s4-\markup{Merge rests as per standard notation practice.}

      \relative c'' { c4 d e r | r2  e4 g | R1 } 

      \\

      \relative c'' { c4 b a r | r a g2   | R1 }

    >>   

 }  

}

  \layout {}

  \midi {}

}