require 'yaml'

class BigDecimal #:nodoc:
  alias :_original_to_s :to_s
  def to_s(format="F")
    _original_to_s(format)
  end

  yaml_as "tag:yaml.org,2002:float"
  def to_yaml( opts = {} )
    YAML::quick_emit( nil, opts ) do |out|
      # This emits the number without any scientific notation.
      # I prefer it to using self.to_f.to_s, which would lose precision.
      #
      # Note that YAML allows that when reconsituting floats
      # to native types, some precision may get lost.
      # There is no full precision real YAML tag that I am aware of.
      str = self.to_s
      if str == "Infinity"
        str = ".Inf"
      elsif str == "-Infinity"
        str = "-.Inf"
      elsif str == "NaN"
        str = ".NaN"
      end
      out.scalar( "tag:yaml.org,2002:float", str, :plain )
    end
  end
end