App Serialization

Notes wrt hacking YAML.

require 'yaml'
require 'test/unit'

class A
  attr_reader :key, :hash, :array
  def initialize(value='value')
    @key = value
    @hash = {:key => value}
    @array = [:key, value]
  end
end

class B
  attr_reader :a
  def initialize(a=A.new)
    @a = a
  end
end


class CustomEmitter < YAML::Syck::Emitter
  module OutExtension
    def map( taguri, to_yaml_style)
      super do |out|
        out.extend MapExtension
        yield(out)
      end
    end
    
    def seq( taguri, to_yaml_style)
      super do |out|
        out.extend SeqExtension
        yield(out)
      end
    end
  end
  
  module MapExtension
    def add( k, v)
      puts [k,v].inspect
      super
    end
  end
  
  module SeqExtension
    def add(v)
      v.inspect
      super
    end
  end
  
  def initialize
    super
    @out.extend OutExtension
  end
end

class TestYAML < Test::Unit::TestCase
  
  def test_yaml_emitter_can_be_extended
    a = A.new
    b = B.new(a)
    
    emitter = CustomEmitter.new.set_resolver( YAML.resolver )
    dump = b.to_yaml(emitter)
    
    d = YAML.load(dump)
    assert_equal 'value', d.a.key
    assert_equal({:key => 'value'}, d.a.hash)
    assert_equal [:key, 'value'], d.a.array
  end
end

Made a nasty hack using the above system before discovering the formatting error that syck produces.