my std out is messed with a lot of debugging output like:

Rules:
  Rule Indent = Indent$1 (12)
  Rule Indent$1 =  (4)
  Rule Indent$1 = <indent> (5)
  Rule Item = Indent Item2 (2)
  Rule Item2 = SequenceValue (0)
  Rule Item2 = MapKey MapValue (1)
  Rule MapKey = <key> (11)
  Rule MapValue = <value> (9)
  Rule S = S$1 (6)
  Rule S$1 =  (7)
  Rule S$1 = S$2 S$1 (8)
  Rule S$2 = Item (10)
  Rule SequenceValue = <sequence> (3)

First:
    Item2 : [0, 1]
      <key> [1]
      <sequence> [0]
    Item : [2]
    SequenceValue : [3]
    Indent$1 : [4, 5] #[4]
      <indent> [5]
    S : [6]
    S$1 : [7, 8] #[7]
      <key> [8]
      <sequence> [8]
      <indent> [8]
    MapValue : [9]
    S$2 : [10]
    MapKey : [11]
    Indent : [12]


...

use proper logging instead.