\version "2.16.0"

\header {
  %title = "Molly Malone"
  composer = "Traditional"
}

<<  
  \chords {s4 c1*6/4 g c g g1*3/4 c}
  \relative g'
  {
    \time 3/4
    \key g \major
    \partial 4 d4 |
    \repeat volta 3 
    {
      g g g |
      g8 b4. a8 g |
      a4 a a |
      a8 c4. b8 a |
      d4 b g |
      d' b g |      
    }
    \alternative 
    {
      {
        \set Score.repeatCommands = #'((volta "1"))        
        e c' b |
        a2 d,4 |
      }
      { 
        \set Score.repeatCommands = #'((volta "2-3") end-repeat)        
        a'4. g8 a4 |
        g2 d4 |
      }      
    }   
    
    \bar "|."
  }
>>