* ext/bigdecimal/lib/bigdecimal/util.rb (Float#to_d): modified for

specifying precision.  fixes #5098.  [ruby-dev:44210]
* test/bigdecimal/test_bigdecimal_util.rb: add test for the above
  change.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@32679 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,11 @@
+Wed Jul 27 00:48:00 2011  Kenta Murata  <mrkn@mrkn.jp>
+
+	* ext/bigdecimal/lib/bigdecimal/util.rb (Float#to_d): modified for
+	  specifying precision.  fixes #5098.  [ruby-dev:44210]
+
+	* test/bigdecimal/test_bigdecimal_util.rb: add test for the above
+	  change.
+
 Wed Jul 27 00:45:00 2011  Kenta Murata  <mrkn@mrkn.jp>
 
 	* ext/bigdecimal/lib/bigdecimal/util.rb (Integer#to_d): added

ext/bigdecimal/lib/bigdecimal/util.rb

@@ -27,8 +27,8 @@ class Float < Numeric
   #     0.5.to_d
   #     # => #<BigDecimal:1dc69e0,'0.5E0',9(18)>
   #
-  def to_d
-    BigDecimal(self.to_s)
+  def to_d(precision=nil)
+    BigDecimal(self, precision || Float::DIG+1)
   end
 end
 

test/bigdecimal/test_bigdecimal_util.rb

@@ -12,4 +12,17 @@ class TestBigDecimalUtil < Test::Unit::TestCase
     assert_equal(BigDecimal(1), 1.to_d)
     assert_equal(BigDecimal(2<<100), (2<<100).to_d)
   end
+
+  def test_Float_to_d_without_precision
+    delta = 1.0/10**(Float::DIG + 1)
+    assert_in_delta(BigDecimal(0.5, Float::DIG+1), 0.5.to_d, delta)
+    assert_in_delta(BigDecimal(355.0/113.0, Float::DIG+1), (355.0/113.0).to_d, delta)
+  end
+
+  def test_Float_to_d_with_precision
+    digits = 5
+    delta = 1.0/10**(digits)
+    assert_in_delta(BigDecimal(0.5, 5), 0.5.to_d(digits), delta)
+    assert_in_delta(BigDecimal(355.0/113.0, 5), (355.0/113.0).to_d(digits), delta)
+  end
 end