class Parser::Source::Map::Index

def initialize(begin_l, end_l, expression_l)
  @begin, @end = begin_l, end_l
  @operator = nil
  super(expression_l)
end

def update_operator(operator_l)
  @operator = operator_l
end

def with_operator(operator_l)
  with { |map| map.update_operator(operator_l) }
end