module LittleGhost::Support

# File lib/little_ghost/support.rb, line 12
def deep_dup(value, ancestors = {})
  if value.is_a?(Hash) || value.is_a?(Array) || value.is_a?(Data)
    identity = value.object_id
    raise ArgumentError, "cyclic values cannot be duplicated" if ancestors.key?(identity)

    ancestors[identity] = true
  end
  case value
  when Hash
    value.each_with_object({}) do |(key, child), copy|
      copy[deep_dup(key, ancestors)] = deep_dup(child, ancestors)
    end
  when Array
    value.map { |child| deep_dup(child, ancestors) }
  when String
    value.dup
  when Data
    value.class.new(**value.to_h.transform_values { |child| deep_dup(child, ancestors) })
  else
    value
  end
ensure
  ancestors.delete(identity) if identity
end