\score {
  \header {
    title = "Sommerpsalm"
    poet = "Text: Carl David af Wirsén"
    composer = "Musik: Waldemar Ahlén (1894-1982)"
    arranger = "dt. Text: Josef Newerkla"
    tagline = ""
  }

  \new ChoirStaff <<
    \set Score.skipBars = ##t
    \new Lyrics = textSopran       { }
    \new Staff <<
      \new Voice = sopran   { \global << \artikulationFrauen \melodieSopran >> }
    >>
    ifdef(`STR_1',`\new Lyrics = textIf            { }')
    ifdef(`STR_2',`\new Lyrics = textIIf           { }')
    ifdef(`STR_3',`\new Lyrics = textIIIf          { }')
    \new Staff <<
      \new Voice = alt      { \global << \artikulationFrauen \melodieAlt >> }
    >>
    \new Staff <<
      \new Voice = tenor    { \global \clef "G_8" << \artikulationMaenner \melodieTenor >> }
    >>
    ifdef(`STR_1',`\new Lyrics = textIm            { }')
    ifdef(`STR_2',`\new Lyrics = textIIm           { }')
    ifdef(`STR_3',`\new Lyrics = textIIIm          { }')
    \new Staff <<
      \new Voice = bass     { \global \clef "bass" << \artikulationMaenner \melodieBass >> }
    >>

    ifdef(`STR_1',`\context Lyrics = textIf       \lyricsto sopran    { \textI }')
    ifdef(`STR_2',`\context Lyrics = textIIf      \lyricsto sopran    { \textII }')
    ifdef(`STR_3',`\context Lyrics = textIIIf     \lyricsto sopran    { \textIII }')
    ifdef(`STR_1',`\context Lyrics = textIm       \lyricsto tenor     { \textI }')
    ifdef(`STR_2',`\context Lyrics = textIIm      \lyricsto tenor     { \textII }')
    ifdef(`STR_3',`\context Lyrics = textIIIm     \lyricsto tenor     { \textIII }')
  >>
  \layout {
    indent = #0
    \context {
      \Staff
      \RemoveEmptyStaves
      \override VerticalAxisGroup #'remove-first = ##t
    }
  }
}