diff --git a/ChangeLog b/ChangeLog
index 28bcd991e3..759f73456d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Nov  7 07:32:55 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* lib/yaml/rubytypes.rb: support Rational and Complex as 1.8
+	  does.  a patch from Hiroshi Moriyama in [ruby-dev:36899].
+
 Fri Nov  7 07:12:06 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* thread_pthread.c (thread_timer): uses pthread_cond_timedwait always
diff --git a/lib/yaml/rubytypes.rb b/lib/yaml/rubytypes.rb
index 35b719196e..ae65b355e1 100644
--- a/lib/yaml/rubytypes.rb
+++ b/lib/yaml/rubytypes.rb
@@ -379,6 +379,44 @@ class Float
 	end
 end
 
+class Rational
+	yaml_as "tag:ruby.yaml.org,2002:object:Rational"
+	def Rational.yaml_new( klass, tag, val )
+		if val.is_a? String
+			Rational( val )
+		else
+			Rational( val['numerator'], val['denominator'] )
+		end
+	end
+	def to_yaml( opts = {} ) 
+		YAML::quick_emit( self, opts ) do |out|
+			out.map( taguri, nil ) do |map| 
+				map.add( 'denominator', denominator )
+				map.add( 'numerator', numerator )
+			end
+		end
+	end
+end
+
+class Complex
+	yaml_as "tag:ruby.yaml.org,2002:object:Complex"
+	def Complex.yaml_new( klass, tag, val )
+		if val.is_a? String
+			Complex( val )
+		else
+			Complex( val['real'], val['image'] )
+		end
+	end
+	def to_yaml( opts = {} )
+		YAML::quick_emit( self, opts ) do |out|
+			out.map( taguri, nil ) do |map|
+				map.add( 'image', imaginary )
+				map.add( 'real', real )
+			end
+		end
+	end
+end
+
 class TrueClass
     yaml_as "tag:yaml.org,2002:bool#yes"
 	def to_yaml( opts = {} )
diff --git a/test/yaml/test_yaml.rb b/test/yaml/test_yaml.rb
index 74a2fa851e..ed94705fcf 100644
--- a/test/yaml/test_yaml.rb
+++ b/test/yaml/test_yaml.rb
@@ -1107,6 +1107,30 @@ EOY
 
 	end
 
+	def test_ruby_rational
+		assert_to_yaml( Rational(1, 2), <<EOY )
+--- !ruby/object:Rational 
+numerator: 1
+denominator: 2
+EOY
+
+		# Read YAML dumped by the ruby 1.8.3.
+		assert_to_yaml( Rational(1, 2), "!ruby/object:Rational 1/2\n" )
+		assert_raise( ArgumentError ) { YAML.load("!ruby/object:Rational INVALID/RATIONAL\n") }
+	end
+
+	def test_ruby_complex
+		assert_to_yaml( Complex(3, 4), <<EOY )
+--- !ruby/object:Complex 
+image: 4
+real: 3
+EOY
+
+		# Read YAML dumped by the ruby 1.8.3.
+		assert_to_yaml( Complex(3, 4), "!ruby/object:Complex 3+4i\n" )
+		assert_raise( ArgumentError ) { YAML.load("!ruby/object:Complex INVALID+COMPLEXi\n") }
+	end
+
 	def test_emitting_indicators
 		assert_to_yaml( "Hi, from Object 1. You passed: please, pretty please", <<EOY
 --- "Hi, from Object 1. You passed: please, pretty please"