Yaml and self-referential data

I have a data structure (Arrays and Hashes mixed in a soup) that is
fairly self-referential, i.e. it has cycles. When I try to do
foo.to_yaml, it complains:

/opt/local/lib/ruby/1.8/yaml.rb:382:in quick_emit': stack level too deep (SystemStackError) from /opt/local/lib/ruby/1.8/yaml/rubytypes.rb:164:into_yaml’
from /opt/local/lib/ruby/1.8/yaml/rubytypes.rb:41:in
node_export' from /opt/local/lib/ruby/1.8/yaml/rubytypes.rb:41:inadd’
from /opt/local/lib/ruby/1.8/yaml/rubytypes.rb:41:in to_yaml' from /opt/local/lib/ruby/1.8/yaml/rubytypes.rb:40:ineach’
from /opt/local/lib/ruby/1.8/yaml/rubytypes.rb:40:in to_yaml' from /opt/local/lib/ruby/1.8/yaml/rubytypes.rb:39:inmap’
from /opt/local/lib/ruby/1.8/yaml/rubytypes.rb:39:in to_yaml' ... 6502 levels... from /opt/local/lib/ruby/1.8/yaml.rb:387:inemit’
from /opt/local/lib/ruby/1.8/yaml.rb:387:in quick_emit' from /opt/local/lib/ruby/1.8/yaml/rubytypes.rb:107:into_yaml’
from ./yaml.rb:43

However, on the small testing scale it works fine:

  • &id004
    name: foo
    famc: &id002
    • &id001
      name: bar
      fams: *id002
      famc: &id005
      • *id001
    • &id003
      name: baz
      fams: *id002
      famc: &id006
      • *id003
    • *id004
  • *id001
  • *id003
  • *id002
  • *id005
  • *id006

Is there anything I can do to help the to_yaml method along? Maybe tell
it to be eager about using aliases or something?