From: Joel VanderWerf <vjoel@...>
Date: 2004-03-25T06:45:37+09:00
Subject: Re: How to avoid duplicate object creations?

Robert Klemme wrote:
> AFAIK there is no hook in Marshal and Yaml that would allow to provide your
> own object creation.  Someone correct me if I'm wrong here.

For Marshalled objects, you can define a YourClass._load and 
YourClass#_dump (note the first is a class method). The former can look 
at the marshalled data as a string and decide what object to create. The 
  latter is what generates that string. See the Pickaxe for details.

In Yaml, it's possible too, if you don't mind defining a custom 
ruby-type, in which case you are allowed to construct an object from the 
yaml data. I'm not sure if there is a hook to do this without defining a 
custom type. For examples, see yaml/rubytypes.rb in your ruby lib. The 
value returned from the block you give to "add_ruby_type" is the value 
that used for the object.