* ext/psych/lib/psych/visitors/to_ruby.rb: BigDecimals can be restored

  from YAML.
* ext/psych/lib/psych/visitors/yaml_tree.rb: BigDecimals can be dumped
  to YAML.
* test/psych/test_numeric.rb: tests for BigDecimal serialization

Fixes #31

CHANGELOG.rdoc

@@ -1,3 +1,11 @@
+Sun Dec 18 12:42:48 2011  Aaron Patterson <aaron@tenderlovemaking.com>
+
+	* ext/psych/lib/psych/visitors/to_ruby.rb: BigDecimals can be restored
+	  from YAML.
+	* ext/psych/lib/psych/visitors/yaml_tree.rb: BigDecimals can be dumped
+	  to YAML.
+	* test/psych/test_numeric.rb: tests for BigDecimal serialization
+
 Sun Dec 18 12:03:13 2011  Aaron Patterson <aaron@tenderlovemaking.com>
 
 	* ext/psych/lib/psych/scalar_scanner.rb: Strings that look like dates

lib/psych/visitors/to_ruby.rb

@@ -52,6 +52,9 @@ def deserialize o
           o.value.unpack('m').first
         when '!str', 'tag:yaml.org,2002:str'
           o.value
+        when '!ruby/object:BigDecimal'
+          require 'bigdecimal'
+          BigDecimal._load o.value
         when "!ruby/object:DateTime"
           require 'date'
           @ss.parse_time(o.value).to_datetime

lib/psych/visitors/yaml_tree.rb

@@ -214,6 +214,10 @@ def visit_Float o
         end
       end
 
+      def visit_BigDecimal o
+        @emitter.scalar o._dump, nil, '!ruby/object:BigDecimal', false, false, Nodes::Scalar::ANY
+      end
+
       def binary? string
         string.encoding == Encoding::ASCII_8BIT ||
           string.index("\x00") ||

test/psych/test_numeric.rb

@@ -1,4 +1,5 @@
 require 'psych/helper'
+require 'bigdecimal'
 
 module Psych
   ###
@@ -10,5 +11,15 @@ def test_non_float_with_0
       str = Psych.load('--- 090')
       assert_equal '090', str
     end
+
+    def test_big_decimal_tag
+      decimal = BigDecimal("12.34")
+      assert_match "!ruby/object:BigDecimal", Psych.dump(decimal)
+    end
+
+    def test_big_decimal_round_trip
+      decimal = BigDecimal("12.34")
+      assert_cycle decimal
+    end
   end
 end