anchor.diff:  segment(_SegmentId, [], _Repetition) ->
       undefined.
   
  +
   -spec segment_count(raw_segment_id() | segment_id(), raw_msg() | msg()) -> non_neg_integer().
   segment_count(SegmentId, Msg) ->
       segment_count(SegmentId, Msg, 0).
  
positive.code: component(Index, DataType, Length, Segment) ->
      ehl7_field:component(Index, DataType, Length, Segment).
  
  
  -spec component(field_index(), raw_segment()) -> raw_field() | undefined.
  component(Index, Segment) ->
      ehl7_field:component(Index, Segment).
  
negative.code: repetition(Index, DataType, Length, Segment) ->
      ehl7_field:repetition(Index, DataType, Length, Segment).
  
  -spec repetition(field_index(), raw_segment()) -> raw_field() | undefined.
  repetition(Index, Segment) ->
      ehl7_field:repetition(Index, Segment).
  