How to write a JSON srteamer

nesting_level_use_case.rb

@aggregator # what to yield
@current_nesting_level # when to yield

@parser.start_object do
  @current_nesting_level += 1
end

@parser.end_object do
  if yield_object?(yield_nesting_level)
    yield @aggregator[@current_nesting_level].clone
    @aggregator = {}
  end

  @current_nesting_level -= 1
end

@parser.key do
# build @agrregator
end

@parser.value do
# build @agrregator
end

def yield_object?(yield_nesting_level)
  @current_nesting_level.eql? yield_nesting_level
end