2 files changed, 9 insertions, 24 deletions
diff --git a/ext/bigdecimal/lib/bigdecimal/jacobian.rb b/ext/bigdecimal/lib/bigdecimal/jacobian.rb
index 84c50248b7..9cad06c09b 100644
--- a/ext/bigdecimal/lib/bigdecimal/jacobian.rb
+++ b/ext/bigdecimal/lib/bigdecimal/jacobian.rb
@@ -21,9 +21,6 @@
 #
 # fx is f.values(x).
 #
-
-require 'bigdecimal'
-
 module Jacobian
   module_function
 
diff --git a/ext/bigdecimal/lib/bigdecimal/util.rb b/ext/bigdecimal/lib/bigdecimal/util.rb
index 88f490cb45..911fa6fe3a 100644
--- a/ext/bigdecimal/lib/bigdecimal/util.rb
+++ b/ext/bigdecimal/lib/bigdecimal/util.rb
@@ -5,8 +5,6 @@
 # and provides BigDecimal#to_d and BigDecimal#to_digits.
 #++
 
-require 'bigdecimal'
-require 'bigdecimal/util.so'
 
 class Integer < Numeric
   # call-seq:
@@ -44,8 +42,8 @@ class Float < Numeric
   #
   # See also BigDecimal::new.
   #
-  def to_d(precision=Float::DIG)
-    BigDecimal(self, precision)
+  def to_d(precision=nil)
+    BigDecimal(self, precision || Float::DIG)
   end
 end
 
@@ -66,6 +64,13 @@ class String
   #
   # See also BigDecimal::new.
   #
+  def to_d
+    begin
+      BigDecimal(self)
+    rescue ArgumentError
+      BigDecimal(0)
+    end
+  end
 end
 
 
@@ -127,20 +132,3 @@ class Rational < Numeric
     BigDecimal(self, precision)
   end
 end
-
-
-class NilClass
-  # call-seq:
-  #     nil.to_d -> bigdecimal
-  #
-  # Returns nil represented as a BigDecimal.
-  #
-  #     require 'bigdecimal'
-  #     require 'bigdecimal/util'
-  #
-  #     nil.to_d   # => 0.0
-  #
-  def to_d
-    BigDecimal(0)
-  end
-end