module TablePrint::HashExtensions::ConstructiveMerge

def constructive_merge(hash)
  target = dup
  hash.keys.each do |key|
    if hash[key].is_a? Hash and self[key].is_a? Hash
      target[key].extend ConstructiveMerge
      target[key] = target[key].constructive_merge(hash[key])
      next
    end
    target[key] = hash[key]
  end
  target
end

def constructive_merge!(hash)
  target = self
  hash.keys.each do |key|
    if hash[key].is_a? Hash and self[key].is_a? Hash
      target[key].extend ConstructiveMerge
      target[key] = target[key].constructive_merge(hash[key])
      next
    end
    target[key] = hash[key]
  end
  target
end