gistfile1.txt

irb(main):001:0> require 'yaml'
=> true
irb(main):002:0> class Foo
irb(main):003:1>   attr_accessor :bar
irb(main):004:1>   attr_accessor :baz
irb(main):005:1>   end
=> nil
irb(main):006:0> a = Foo.new
=> #<Foo:0x3d6dbe0>
irb(main):007:0> a.bar = "abc"
=> "abc"
irb(main):008:0> a.baz = "def"
=> "def"
irb(main):009:0> a.to_yaml
=> "--- !ruby/object:Foo \nbar: abc\nbaz: def\n"
irb(main):010:0> class Bar
irb(main):011:1>   attr_accessor :foo
irb(main):012:1>   attr_accessor :baz
irb(main):013:1>   def to_yaml_properties
irb(main):014:2>     ["@baz"]
irb(main):015:2>     end
irb(main):016:1>   end
=> nil
irb(main):017:0> b = Bar.new
=> #<Bar:0x3d13dc0>
irb(main):018:0> b.foo = "abc"
=> "abc"
irb(main):019:0> b.baz = "def"
=> "def"
irb(main):020:0> b.to_yaml
=> "--- !ruby/object:Bar \nbaz: def\n"