Start
  prog
    Nodes[Ns]
      s_assign
        id@(1:1-1:2)='a'
        '='@(1:3-1:4)
        e_lit
          int@(1:5-1:6)='5'
        ';'@(1:6-1:7)
      s_print
        'print'@(2:1-2:6)
        '('@(2:6-2:7)
        e_add
          e_var
            id@(2:7-2:8)='a'
          '+'@(2:8-2:9)
          e_lit
            int@(2:9-2:10)='2'
        ')'@(2:10-2:11)
        ';'@(2:11-2:12)
  Eof@(3:1-3:1)=''