Bahuvrihi Tap (Task Application)

Comments and changes to this ticket

• 

  bahuvrihi March 21st, 2009 @ 11:36 AM

  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
  

• 

  bahuvrihi March 21st, 2009 @ 01:23 PM

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

  • yaml_hack.txt 6 KB
• 

  bahuvrihi March 22nd, 2009 @ 09:24 AM

  • State changed from “new” to “resolved”
  • Assigned user set to “bahuvrihi”

  The current solution is acceptable. Pure-YAML serialization that removes any Proc or Threads. This allows the YAML to be re-loaded and inspected, even reconstructed for re-use.

  It will have issues because the dump/reload is not totally faithful, but as an 80% I think it goes.