class RBS::CLI

def run_ancestors(args, options)
  # @type var kind: :instance | :singleton
  kind = :instance
  OptionParser.new do |opts|
    opts.banner = <<EOU
e: rbs ancestors [options...] [type_name]
 ancestors of the given class or module.
ples:
rbs ancestors --instance String
rbs ancestors --singleton Array
ons:
    opts.on("--instance", "Ancestors of instance of the given type_name (default)") { kind = :instance }
    opts.on("--singleton", "Ancestors of singleton of the given type_name") { kind = :singleton }
  end.order!(args)
  loader = options.loader()
  env = Environment.from_loader(loader).resolve_type_names
  builder = DefinitionBuilder::AncestorBuilder.new(env: env)
  type_name = TypeName(args[0]).absolute!
  if env.class_decls.key?(type_name)
    ancestors = case kind
                when :instance
                  builder.instance_ancestors(type_name)
                when :singleton
                  builder.singleton_ancestors(type_name)
                else
                  raise
                end
    ancestors.ancestors.each do |ancestor|
      case ancestor
      when Definition::Ancestor::Singleton
        stdout.puts "singleton(#{ancestor.name})"
      when Definition::Ancestor::Instance
        if ancestor.args.empty?
          stdout.puts ancestor.name.to_s
        else
          stdout.puts "#{ancestor.name}[#{ancestor.args.join(", ")}]"
        end
      end
    end
  else
    stdout.puts "Cannot find class: #{type_name}"
  end
end