From: Daniel Schierbeck <daniel.schierbeck@...>
Date: 2005-12-14T02:17:39+09:00
Subject: Concerning the #to_* convention

Howdy partners! I'm having a bit of fun writing a Ruby XML document 
object model (yes, I'm aware of the fact that there already exists such 
models), and I'm using #to_* throughout the code. I'm just wondering if 
a #to_* method always should return a copy of the receiver, in the 
format specified by * (e.g. `str', `i'), or if it's okay to just pass a 
reference to the receiver itself?

Consider this:

   class Namespace
     def to_xml_ns
       self  # should this be a copy?
     end
   end

   class Element < Node
     def initialize(opts = {})
       if opts[:namespace]
         # `namespace' quacks like a Namespace object
         if opts[:namespace].respond_to? :to_xml_ns
           # I'd like a Namespace object in @namespace.
           @namespace = opts[:namespace].to_xml_ns
         # `namespace' quakcs like a String object
         elsif opts[:namespace].respond_to? :to_str
           @namespace = Namespace.new(:uri => opts[:namespace].to_str, 
opts[:prefix])
         end
       end
     end
   end


I hope you can give me a hint of what the best practice is.


Cheers,
Daniel