Spacing notes using an invisible staff

When entering partially typeset music (i.e. for students to be completed by hand), you may need the spacing that correspond to the timing of notes: all measures have same length, etc. It can be implemented by adding an invisible staff with a lot of fast notes.

\version "2.24"

%% http://lsr.di.unimi.it/LSR/Item?id=126

%LSR modified by P.P.Schneider on Feb.2014

quickmeasure =  {
  \hideNotes
  \repeat unfold 64 c''16
}

mel =  \relative c' { 
  c16 d16 e8 a4 g2 
  e8 d c2. 
  g'1 
  e4 d c2 
}

\score {
  \context PianoStaff  <<
    \new Staff <<
      \clef G
      \new Voice { \mel }
      \new Voice { \quickmeasure }
    >>
    \new Staff  { 
      \clef F 
      s1*4 
    }
  >>
  \layout {}
}