From: Ben Giddings <bg-rubytalk@...>
Date: 2004-07-28T11:56:12+09:00
Subject: Writing a custom YAML emitter

Hi all,

I'm trying to understand how to write a custom YAML emitter.  As fun 
and interesting as Why's documentation is, I don't quite get how to do 
what I need.

What I'm looking for is a way of avoiding emitting certain instance 
variables.  Say I have a class like this:

class Book
   attr_accessor :title, :chapter_titles
   attr_accessor :current_page
end

When I save it, I want to save the permanent features like "title" and 
"chapter_titles", but I want to forget the current page.

I think the YAML representation would be something like:

--- !ruby/object:Bar
title: Fun with YAML
chapter_titles:
   - your first yaml document
   - daily yaml chores
   - advanced yaml fun

 From looking at "rubytypes.rb", it looks like if I redefine 
"to_yaml_properties" to return ["@title", "@chapter_titles"] it should 
work.  But is this the right way?  Is there another preferred way?

Ben