1 files changed, 23 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/core_ext/bigdecimal/conversions.rb b/activesupport/lib/active_support/core_ext/bigdecimal/conversions.rb
index dcdb08aea0..d2504302cd 100644
--- a/activesupport/lib/active_support/core_ext/bigdecimal/conversions.rb
+++ b/activesupport/lib/active_support/core_ext/bigdecimal/conversions.rb
@@ -1,6 +1,29 @@
+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