explained at http://tagaholic.blogspot.com/2009/01/simple-block-to-hash-conversion-for.html

gistfile1.rb

require 'ostruct'

class ConfigStruct < OpenStruct
  def self.block_to_hash(block=nil)
    config = self.new
    if block
      block.call(config)
      config.to_hash
    else
      {}
    end
  end

  def to_hash
    @table
  end
end