如何获得在Ruby1.9.1上工作的to-yaml方法的格式化选项?

根据YAML文档,可以通过 hash of options 致 .to_yaml 方法。

当前,当我传递文档建议的选项时,它不起作用,哈希将被忽略。

irb(main):001:0> require 'yaml'
=> true
irb(main):002:0> user = { "1" => { "name" => "john", "age" => 44 } }
user.to_yaml
=> "--- \n\"1\": \n  name: john\n  age: 44\n"

现在,传递一些选项:

irb(main):014:0> user.to_yaml( :Indent => 4, :UseHeader => true, :UseVersion => true )
=> "--- \n\"1\": \n  name: john\n  age: 44\n"
irb(main):015:0> user.to_yaml( :Separator => "\n" )
=> "--- \n\"1\": \n  name: john\n  age: 44\n"
irb(main):016:0> user.to_yaml( :separator => "\n" )
=> "--- \n\"1\": \n  name: john\n  age: 44\n"
irb(main):017:0> RUBY_VERSION
=> "1.9.1"

如您所见,传递选项不起作用。只有默认值:

YAML::DEFAULTS
=> {:Indent=>2, :UseHeader=>false, :UseVersion=>false, :Version=>"1.0", :SortKeys=>false, :AnchorFormat=>"id%03d", :ExplicitTypes=>false, :WidthType=>"absolute", :BestWidth=>80, :UseBlock=>false, :UseFold=>false, :Encoding=>:None}

这是已知的虫子吗?或者它目前正在为任何使用Ruby1.9.1的人工作?