YAML has inheritance. The most clear example I have ever seen is here: http://blog.101ideas.cz/posts/dry-your-yaml-files.html

I need something more complex: I need to override object's object's property. Here is an example:

database: &default
  server:
    ip: 192.168.1.5
    port: 2000
  db_name: test
  user: 
    name: root
    password: root

# database foo differs from default by only its port and user password
foo_database:
  <<: *default
  server:
    port: 2001
  db_name: foo
  user:
    password: foo_root

I want to get this result:

foo_database.server.ip -> 192.168.1.5
foo_database.server.port -> 2001
foo_database.db_name -> foo
foo_database.user.name -> root
foo_database.user.password -> foo_root

But if you declare like this, you will get these properties incorrect (according to expected values):

foo_database.server.ip -> will be None
foo_database.user.name -> will be None

because new "server" object has only "port" property and it overrides whole old "server" object.

How do I get the kind of inheritance which I want to achieve?

Edit

Here is my exact intention with a working code in LiveScript:

config = 
  default: 
    ip: \192.168.1.5
    port: 2000
    name: \root 
    password: \root 
    db:
      name: \default
      location: \LA

  foo-database:~ -> @default `merge` do 
    ip: \11.11.11.11
    db:
      name: \my-foo 

  bar-database:~ -> @foo-database `merge` do 
    password: \1234 
    db:
      location: \SF

config.default 
# => {"ip":"192.168.1.5","port":2000,"name":"r