Alternate lyrics context for song sheets

When preparing song sheets, it's sometimes useful to have the lyrics of all the verses inside the score, correctly lined up to the notes. However, this makes it easy for the singer to mix up verses -- especially when changing systems. A common solution is to alternate the display properties of the lyric lines. This snippet demonstrates how to use such an approach in LilyPond.

\version "2.24"

%% http://lsr.di.unimi.it/LSR/Item?id=641

%% Implement an alternate lyric context
\layout {
  \context {
    \Lyrics
    \name AltLyrics
    \alias Lyrics
    \override StanzaNumber.font-series = #'medium
    \override LyricText.font-shape = #'italic
    \override LyricText.color = #(x11-color 'grey20)
  }
  \context {
    \StaffGroup
    \accepts AltLyrics
  }
}

%% Doesn't do a lot, apart from avoid warnings when generating midi output
\midi {
  \context {
    \Lyrics
    \name AltLyrics
    \alias Lyrics
  }
  \context {
    \StaffGroup
    \accepts AltLyrics
  }
}

<<
  \new Staff {
    \new Voice = "notes" \relative c' {
      f4 a a a
    }
  }
  \new Lyrics \lyricsto "notes" {
    \set stanza = #"1."
    Hey non -- ny no
  }
  \new AltLyrics \lyricsto "notes" {
    \set stanza = #"2."
    Fa la la la
  }
  \new Lyrics \lyricsto "notes" {
    \set stanza = #"3."
    Fid -- dle di dee
  }
  \new AltLyrics \lyricsto "notes" {
    \set stanza = #"4."
    Da da da dum
  }
>>