Implement to_d in Numeric and with the same number of arguments everywhere

This allows user code to be more generic, not having to care
about the specific class.

Preserve the BigDecimal override to allow returning the same object.

Author: fsateler

lib/bigdecimal/util.rb

@@ -7,31 +7,13 @@
 
 require 'bigdecimal'
 
-class Integer < Numeric
+class Numeric
   # call-seq:
-  #     int.to_d  -> bigdecimal
+  #     num.to_d  -> bigdecimal
+  #     num.to_d(precision)  -> bigdecimal
   #
-  # Returns the value of +int+ as a BigDecimal.
-  #
-  #     require 'bigdecimal'
-  #     require 'bigdecimal/util'
-  #
-  #     42.to_d   # => 0.42e2
-  #
-  # See also Kernel.BigDecimal.
-  #
-  def to_d
-    BigDecimal(self)
-  end
-end
-
-
-class Float < Numeric
-  # call-seq:
-  #     float.to_d             -> bigdecimal
-  #     float.to_d(precision)  -> bigdecimal
+  # Returns the value as a BigDecimal.
   #
-  # Returns the value of +float+ as a BigDecimal.
   # The +precision+ parameter is used to determine the number of
   # significant digits for the result. When +precision+ is set to +0+,
   # the number of digits to represent the float being converted is determined
@@ -41,18 +23,16 @@ class Float < Numeric
   #     require 'bigdecimal'
   #     require 'bigdecimal/util'
   #
-  #     0.5.to_d         # => 0.5e0
-  #     1.234.to_d       # => 0.1234e1
-  #     1.234.to_d(2)    # => 0.12e1
+  #     Rational(22, 7).to_d(3)   # => 0.314e1
+  #     3.14.to_d(3)   # => 0.314e1
+  #     3.to_d(3)   # => 0.3e1
   #
   # See also Kernel.BigDecimal.
-  #
   def to_d(precision=0)
     BigDecimal(self, precision)
   end
 end
 
-
 class String
   # call-seq:
   #     str.to_d  -> bigdecimal
@@ -108,32 +88,7 @@ def to_digits
   #     d.to_d                       # => 0.314e1
   #
   def to_d
-    self
-  end
-end
-
-
-class Rational < Numeric
-  # call-seq:
-  #     rat.to_d(precision)  -> bigdecimal
-  #
-  # Returns the value as a BigDecimal.
-  #
-  # The +precision+ parameter is used to determine the number of
-  # significant digits for the result. When +precision+ is set to +0+,
-  # the number of digits to represent the float being converted is determined
-  # automatically.
-  # The default +precision+ is +0+.
-  #
-  #     require 'bigdecimal'
-  #     require 'bigdecimal/util'
-  #
-  #     Rational(22, 7).to_d(3)   # => 0.314e1
-  #
-  # See also Kernel.BigDecimal.
-  #
-  def to_d(precision=0)
-    BigDecimal(self, precision)
+    self # override to return the same object
   end
 end
 
@@ -180,7 +135,7 @@ class NilClass
   #
   #     nil.to_d   # => 0.0
   #
-  def to_d
-    BigDecimal(0)
+  def to_d(precision=0)
+    BigDecimal(0, precision)
   end
 end